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VC4: Add a module parameter for the screen resolution #1

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@gohai gohai commented Feb 10, 2015

Signed-off-by: Gottfried Haider [email protected]

anholt pushed a commit that referenced this pull request Apr 21, 2015
Open vSwitch allows moving internal vport to different namespace
while still connected to the bridge. But when namespace deleted
OVS does not detach these vports, that results in dangling
pointer to netdevice which causes kernel panic as follows.
This issue is fixed by detaching all ovs ports from the deleted
namespace at net-exit.

BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: [<ffffffffa0aadaa5>] ovs_vport_locate+0x35/0x80 [openvswitch]
Oops: 0000 [#1] SMP
Call Trace:
 [<ffffffffa0aa6391>] lookup_vport+0x21/0xd0 [openvswitch]
 [<ffffffffa0aa65f9>] ovs_vport_cmd_get+0x59/0xf0 [openvswitch]
 [<ffffffff8167e07c>] genl_family_rcv_msg+0x1bc/0x3e0
 [<ffffffff8167e319>] genl_rcv_msg+0x79/0xc0
 [<ffffffff8167d919>] netlink_rcv_skb+0xb9/0xe0
 [<ffffffff8167deac>] genl_rcv+0x2c/0x40
 [<ffffffff8167cffd>] netlink_unicast+0x12d/0x1c0
 [<ffffffff8167d3da>] netlink_sendmsg+0x34a/0x6b0
 [<ffffffff8162e140>] sock_sendmsg+0xa0/0xe0
 [<ffffffff8162e5e8>] ___sys_sendmsg+0x408/0x420
 [<ffffffff8162f541>] __sys_sendmsg+0x51/0x90
 [<ffffffff8162f592>] SyS_sendmsg+0x12/0x20
 [<ffffffff81764ee9>] system_call_fastpath+0x12/0x17

Reported-by: Assaf Muller <[email protected]>
Fixes: 46df7b8("openvswitch: Add support for network namespaces.")
Signed-off-by: Pravin B Shelar <[email protected]>
Reviewed-by: Thomas Graf <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
mapping->host can be NULL and shouldn't be dereferenced before being checked.

[ 1295.741844] GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] SMP KASAN
[ 1295.746387] Dumping ftrace buffer:
[ 1295.748217]    (ftrace buffer empty)
[ 1295.749527] Modules linked in:
[ 1295.750268] CPU: 62 PID: 23410 Comm: trinity-c70 Not tainted 3.19.0-next-20150219-sasha-00045-g9130270f raspberrypi#1939
[ 1295.750268] task: ffff8803a49db000 ti: ffff8803a4dc8000 task.ti: ffff8803a4dc8000
[ 1295.750268] RIP: shmem_mapping (mm/shmem.c:1458)
[ 1295.750268] RSP: 0000:ffff8803a4dcfbf8  EFLAGS: 00010206
[ 1295.750268] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 00000000000f2804
[ 1295.750268] RDX: 0000000000000005 RSI: 0400000000000794 RDI: 0000000000000028
[ 1295.750268] RBP: ffff8803a4dcfc08 R08: 0000000000000000 R09: 00000000031de000
[ 1295.750268] R10: dffffc0000000000 R11: 00000000031c1000 R12: 0400000000000794
[ 1295.750268] R13: 00000000031c2000 R14: 00000000031de000 R15: ffff880e3bdc1000
[ 1295.750268] FS:  00007f8703c7e700(0000) GS:ffff881164800000(0000) knlGS:0000000000000000
[ 1295.750268] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1295.750268] CR2: 0000000004e58000 CR3: 00000003a9f3c000 CR4: 00000000000007a0
[ 1295.750268] DR0: ffffffff81000000 DR1: 0000009494949494 DR2: 0000000000000000
[ 1295.750268] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000000d0602
[ 1295.750268] Stack:
[ 1295.750268]  ffff8803a4dcfec8 ffffffffbb1dc770 ffff8803a4dcfc38 ffffffffad6f230b
[ 1295.750268]  ffffffffad6f2b0d 0000014100000000 ffff88001e17c08b ffff880d9453fe08
[ 1295.750268]  ffff8803a4dcfd18 ffffffffad6f2ce2 ffff8803a49dbcd8 ffff8803a49dbce0
[ 1295.750268] Call Trace:
[ 1295.750268] mincore_page (mm/mincore.c:61)
[ 1295.750268] ? mincore_pte_range (include/linux/spinlock.h:312 mm/mincore.c:131)
[ 1295.750268] mincore_pte_range (mm/mincore.c:151)
[ 1295.750268] ? mincore_unmapped_range (mm/mincore.c:113)
[ 1295.750268] __walk_page_range (mm/pagewalk.c:51 mm/pagewalk.c:90 mm/pagewalk.c:116 mm/pagewalk.c:204)
[ 1295.750268] walk_page_range (mm/pagewalk.c:275)
[ 1295.750268] SyS_mincore (mm/mincore.c:191 mm/mincore.c:253 mm/mincore.c:220)
[ 1295.750268] ? mincore_pte_range (mm/mincore.c:220)
[ 1295.750268] ? mincore_unmapped_range (mm/mincore.c:113)
[ 1295.750268] ? __mincore_unmapped_range (mm/mincore.c:105)
[ 1295.750268] ? ptlock_free (mm/mincore.c:24)
[ 1295.750268] ? syscall_trace_enter (arch/x86/kernel/ptrace.c:1610)
[ 1295.750268] ia32_do_call (arch/x86/ia32/ia32entry.S:446)
[ 1295.750268] Code: e5 48 c1 ea 03 53 48 89 fb 48 83 ec 08 80 3c 02 00 75 4f 48 b8 00 00 00 00 00 fc ff df 48 8b 1b 48 8d 7b 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 3f 48 b8 00 00 00 00 00 fc ff df 48 8b 5b 28 48

All code
========
   0:	e5 48                	in     $0x48,%eax
   2:	c1 ea 03             	shr    $0x3,%edx
   5:	53                   	push   %rbx
   6:	48 89 fb             	mov    %rdi,%rbx
   9:	48 83 ec 08          	sub    $0x8,%rsp
   d:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
  11:	75 4f                	jne    0x62
  13:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1a:	fc ff df
  1d:	48 8b 1b             	mov    (%rbx),%rbx
  20:	48 8d 7b 28          	lea    0x28(%rbx),%rdi
  24:	48 89 fa             	mov    %rdi,%rdx
  27:	48 c1 ea 03          	shr    $0x3,%rdx
  2b:*	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)		<-- trapping instruction
  2f:	75 3f                	jne    0x70
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	48 8b 5b 28          	mov    0x28(%rbx),%rbx
  3f:	48                   	rex.W
	...

Code starting with the faulting instruction
===========================================
   0:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   4:	75 3f                	jne    0x45
   6:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
   d:	fc ff df
  10:	48 8b 5b 28          	mov    0x28(%rbx),%rbx
  14:	48                   	rex.W
	...
[ 1295.750268] RIP shmem_mapping (mm/shmem.c:1458)
[ 1295.750268]  RSP <ffff8803a4dcfbf8>

Fixes: 97b713b ("fs: kill BDI_CAP_SWAP_BACKED")
Signed-off-by: Sasha Levin <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
As soon as the interrupt has been enabled by devm_request_irq(), the
interrupt routine may be called, depending on the current status of the
hardware.

However, at that point rcar_thermal_common hasn't been initialized
complely yet. E.g. rcar_thermal_common.base is still NULL, causing a
NULL pointer dereference:

    Unable to handle kernel NULL pointer dereference at virtual address 0000000c
    pgd = c0004000
    [0000000c] *pgd=00000000
    Internal error: Oops: 5 [#1] SMP ARM
    CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc7-ape6evm-04564-gb6e46cb7cbe82389 #30
    Hardware name: Generic R8A73A4 (Flattened Device Tree)
    task: ee8953c0 ti: ee896000 task.ti: ee896000
    PC is at rcar_thermal_irq+0x1c/0xf0
    LR is at _raw_spin_lock_irqsave+0x48/0x54

Postpone the call to devm_request_irq() until all initialization has
been done to fix this.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Acked-by: Kuninori Morimoto <[email protected]>
Signed-off-by: Eduardo Valentin <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
As the devicetree binding doesn't require num_cs to exist or be strictly
positive, and neither does the platform data case, a bug appear when
num_cs is set to 0 and panics the kernel.

The issue is that in alloc_nand_resource(), chip is dereferenced without
having a value assigned when num_cs == 0.

Fix this by returning ENODEV is num_cs == 0.

The panic seen is :
Unable to handle kernel NULL pointer dereference at virtual address 000002b8
pgd = c0004000
[000002b8] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT ARM
Modules linked in:
Hardware name: Marvell PXA3xx (Device Tree Support)
task: c3822aa0 ti: c3826000 task.ti: c3826000
PC is at alloc_nand_resource+0x180/0x4a8
LR is at alloc_nand_resource+0xa0/0x4a8
pc : [<c0275b90>]    lr : [<c0275ab0>]    psr: 68000013
sp : c3827d90  ip : 00000000  fp : 00000000
r10: c3862200  r9 : 0000005e  r8 : 00000000
r7 : c3865610  r6 : c3862210  r5 : c3924210  r4 : c3862200
r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : 00000000
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
Control: 0000397f  Table: 80004018  DAC: 00000035
Process swapper (pid: 1, stack limit = 0xc3826198)
Stack: (0xc3827d90 to 0xc3828000)
...zip...
[<c0275b90>] (alloc_nand_resource) from [<c0275ff8>] (pxa3xx_nand_probe+0x140/0x978)
[<c0275ff8>] (pxa3xx_nand_probe) from [<c0258c40>] (platform_drv_probe+0x48/0xa4)
[<c0258c40>] (platform_drv_probe) from [<c0257650>] (driver_probe_device+0x80/0x21c)
[<c0257650>] (driver_probe_device) from [<c0257878>] (__driver_attach+0x8c/0x90)
[<c0257878>] (__driver_attach) from [<c0255ec4>] (bus_for_each_dev+0x58/0x88)
[<c0255ec4>] (bus_for_each_dev) from [<c0256ec8>] (bus_add_driver+0xd8/0x1d4)
[<c0256ec8>] (bus_add_driver) from [<c0257f14>] (driver_register+0x78/0xf4)
[<c0257f14>] (driver_register) from [<c00088a8>] (do_one_initcall+0x80/0x1e4)
[<c00088a8>] (do_one_initcall) from [<c048ed08>] (kernel_init_freeable+0xec/0x1b4)
[<c048ed08>] (kernel_init_freeable) from [<c0377d8c>] (kernel_init+0x8/0xe4)
[<c0377d8c>] (kernel_init) from [<c00095f8>] (ret_from_fork+0x14/0x3c)
Code: e503b234 e5953008 e1530001 caffffd1 (e59002b8)
---[ end trace a5770060c8441895 ]---

Signed-off-by: Robert Jarzmik <[email protected]>
Acked-by: Ezequiel Garcia <[email protected]>
Signed-off-by: Brian Norris <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
We did a failed attempt in the past to only use rcu in rtnl dump
operations (commit e67f88d "net: dont hold rtnl mutex during
netlink dump callbacks")

Now that dumps are holding RTNL anyway, there is no need to also
use rcu locking, as it forbids any scheduling ability, like
GFP_KERNEL allocations that controlling path should use instead
of GFP_ATOMIC whenever possible.

This should fix following splat Cong Wang reported :

 [ INFO: suspicious RCU usage. ]
 3.19.0+ raspberrypi#805 Tainted: G        W

 include/linux/rcupdate.h:538 Illegal context switch in RCU read-side critical section!

 other info that might help us debug this:

 rcu_scheduler_active = 1, debug_locks = 0
 2 locks held by ip/771:
  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff8182b8f4>] netlink_dump+0x21/0x26c
  #1:  (rcu_read_lock){......}, at: [<ffffffff817d785b>] rcu_read_lock+0x0/0x6e

 stack backtrace:
 CPU: 3 PID: 771 Comm: ip Tainted: G        W       3.19.0+ raspberrypi#805
 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  0000000000000001 ffff8800d51e7718 ffffffff81a27457 0000000029e729e6
  ffff8800d6108000 ffff8800d51e7748 ffffffff810b539b ffffffff820013dd
  00000000000001c8 0000000000000000 ffff8800d7448088 ffff8800d51e7758
 Call Trace:
  [<ffffffff81a27457>] dump_stack+0x4c/0x65
  [<ffffffff810b539b>] lockdep_rcu_suspicious+0x107/0x110
  [<ffffffff8109796f>] rcu_preempt_sleep_check+0x45/0x47
  [<ffffffff8109e457>] ___might_sleep+0x1d/0x1cb
  [<ffffffff8109e67d>] __might_sleep+0x78/0x80
  [<ffffffff814b9b1f>] idr_alloc+0x45/0xd1
  [<ffffffff810cb7ab>] ? rcu_read_lock_held+0x3b/0x3d
  [<ffffffff814b9f9d>] ? idr_for_each+0x53/0x101
  [<ffffffff817c1383>] alloc_netid+0x61/0x69
  [<ffffffff817c14c3>] __peernet2id+0x79/0x8d
  [<ffffffff817c1ab7>] peernet2id+0x13/0x1f
  [<ffffffff817d8673>] rtnl_fill_ifinfo+0xa8d/0xc20
  [<ffffffff810b17d9>] ? __lock_is_held+0x39/0x52
  [<ffffffff817d894f>] rtnl_dump_ifinfo+0x149/0x213
  [<ffffffff8182b9c2>] netlink_dump+0xef/0x26c
  [<ffffffff8182bcba>] netlink_recvmsg+0x17b/0x2c5
  [<ffffffff817b0adc>] __sock_recvmsg+0x4e/0x59
  [<ffffffff817b1b40>] sock_recvmsg+0x3f/0x51
  [<ffffffff817b1f9a>] ___sys_recvmsg+0xf6/0x1d9
  [<ffffffff8115dc67>] ? handle_pte_fault+0x6e1/0xd3d
  [<ffffffff8100a3a0>] ? native_sched_clock+0x35/0x37
  [<ffffffff8109f45b>] ? sched_clock_local+0x12/0x72
  [<ffffffff8109f6ac>] ? sched_clock_cpu+0x9e/0xb7
  [<ffffffff810cb7ab>] ? rcu_read_lock_held+0x3b/0x3d
  [<ffffffff811abde8>] ? __fcheck_files+0x4c/0x58
  [<ffffffff811ac556>] ? __fget_light+0x2d/0x52
  [<ffffffff817b376f>] __sys_recvmsg+0x42/0x60
  [<ffffffff817b379f>] SyS_recvmsg+0x12/0x1c

Signed-off-by: Eric Dumazet <[email protected]>
Fixes: 0c7aecd ("netns: add rtnl cmd to add and get peer netns ids")
Cc: Nicolas Dichtel <[email protected]>
Reported-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
During system reboot, the sh-dma-engine device may be runtime-suspended,
causing a crash:

    Unhandled fault: imprecise external abort (0x1406) at 0x0002c02c
    Internal error: : 1406 [#1] SMP ARM
    ...
    PC is at sh_dmae_ctl_stop+0x28/0x64
    LR is at sh_dmae_ctl_stop+0x24/0x64

If the sh-dma-engine is runtime-suspended, its module clock is turned
off, and its registers cannot be accessed.

To fix this, move the call to sh_dmae_ctl_stop(), which touches the
DMAOR register, to the sh_dmae_suspend() and sh_dmae_runtime_suspend()
callbacks.  This makes PM operations more symmetric, as both
sh_dmae_resume() and sh_dmae_runtime_resume() already call sh_dmae_rst()
to re-initialize the DMAOR register.

Remove sh_dmae_shutdown(), as it became empty.

Signed-off-by: Geert Uytterhoeven <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Signed-off-by: Vinod Koul <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
We can have multiple fsync operations against the same file during the
same transaction and they can collect the same ordered extents while they
don't complete (still accessible from the inode's ordered tree). If this
happens, those ordered extents will never get their reference counts
decremented to 0, leading to memory leaks and inode leaks (an iput for an
ordered extent's inode is scheduled only when the ordered extent's refcount
drops to 0). The following sequence diagram explains this race:

         CPU 1                                         CPU 2

btrfs_sync_file()

                                                 btrfs_sync_file()

  mutex_lock(inode->i_mutex)
  btrfs_log_inode()
    btrfs_get_logged_extents()
      --> collects ordered extent X
      --> increments ordered
          extent X's refcount
    btrfs_submit_logged_extents()
  mutex_unlock(inode->i_mutex)

                                                   mutex_lock(inode->i_mutex)
  btrfs_sync_log()
     btrfs_wait_logged_extents()
       --> list_del_init(&ordered->log_list)
                                                     btrfs_log_inode()
                                                       btrfs_get_logged_extents()
                                                         --> Adds ordered extent X
                                                             to logged_list because
                                                             at this point:
                                                             list_empty(&ordered->log_list)
                                                             && test_bit(BTRFS_ORDERED_LOGGED,
                                                                         &ordered->flags) == 0
                                                         --> Increments ordered extent
                                                             X's refcount
       --> check if ordered extent's io is
           finished or not, start it if
           necessary and wait for it to finish
       --> sets bit BTRFS_ORDERED_LOGGED
           on ordered extent X's flags
           and adds it to trans->ordered
  btrfs_sync_log() finishes

                                                       btrfs_submit_logged_extents()
                                                     btrfs_log_inode() finishes
                                                   mutex_unlock(inode->i_mutex)

btrfs_sync_file() finishes

                                                   btrfs_sync_log()
                                                      btrfs_wait_logged_extents()
                                                        --> Sees ordered extent X has the
                                                            bit BTRFS_ORDERED_LOGGED set in
                                                            its flags
                                                        --> X's refcount is untouched
                                                   btrfs_sync_log() finishes

                                                 btrfs_sync_file() finishes

btrfs_commit_transaction()
  --> called by transaction kthread for e.g.
  btrfs_wait_pending_ordered()
    --> waits for ordered extent X to
        complete
    --> decrements ordered extent X's
        refcount by 1 only, corresponding
        to the increment done by the fsync
        task ran by CPU 1

In the scenario of the above diagram, after the transaction commit,
the ordered extent will remain with a refcount of 1 forever, leaking
the ordered extent structure and preventing the i_count of its inode
from ever decreasing to 0, since the delayed iput is scheduled only
when the ordered extent's refcount drops to 0, preventing the inode
from ever being evicted by the VFS.

Fix this by using the flag BTRFS_ORDERED_LOGGED differently. Use it to
mean that an ordered extent is already being processed by an fsync call,
which will attach it to the current transaction, preventing it from being
collected by subsequent fsync operations against the same inode.

This race was introduced with the following change (added in 3.19 and
backported to stable 3.18 and 3.17):

  Btrfs: make sure logged extents complete in the current transaction V3
  commit 50d9aa9

I ran into this issue while running xfstests/generic/113 in a loop, which
failed about 1 out of 10 runs with the following warning in dmesg:

[ 2612.440038] WARNING: CPU: 4 PID: 22057 at fs/btrfs/disk-io.c:3558 free_fs_root+0x36/0x133 [btrfs]()
[ 2612.442810] Modules linked in: btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop processor parport_pc parport psmouse therma
l_sys i2c_piix4 serio_raw pcspkr evdev microcode button i2c_core ext4 crc16 jbd2 mbcache sd_mod sg sr_mod cdrom virtio_scsi ata_generic virtio_pci ata_piix virtio_ring libata virtio flo
ppy e1000 scsi_mod [last unloaded: btrfs]
[ 2612.452711] CPU: 4 PID: 22057 Comm: umount Tainted: G        W      3.19.0-rc5-btrfs-next-4+ #1
[ 2612.454921] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
[ 2612.457709]  0000000000000009 ffff8801342c3c78 ffffffff8142425e ffff88023ec8f2d8
[ 2612.459829]  0000000000000000 ffff8801342c3cb8 ffffffff81045308 ffff880046460000
[ 2612.461564]  ffffffffa036da56 ffff88003d07b000 ffff880046460000 ffff880046460068
[ 2612.463163] Call Trace:
[ 2612.463719]  [<ffffffff8142425e>] dump_stack+0x4c/0x65
[ 2612.464789]  [<ffffffff81045308>] warn_slowpath_common+0xa1/0xbb
[ 2612.466026]  [<ffffffffa036da56>] ? free_fs_root+0x36/0x133 [btrfs]
[ 2612.467247]  [<ffffffff810453c5>] warn_slowpath_null+0x1a/0x1c
[ 2612.468416]  [<ffffffffa036da56>] free_fs_root+0x36/0x133 [btrfs]
[ 2612.469625]  [<ffffffffa036f2a7>] btrfs_drop_and_free_fs_root+0x93/0x9b [btrfs]
[ 2612.471251]  [<ffffffffa036f353>] btrfs_free_fs_roots+0xa4/0xd6 [btrfs]
[ 2612.472536]  [<ffffffff8142612e>] ? wait_for_completion+0x24/0x26
[ 2612.473742]  [<ffffffffa0370bbc>] close_ctree+0x1f3/0x33c [btrfs]
[ 2612.475477]  [<ffffffff81059d1d>] ? destroy_workqueue+0x148/0x1ba
[ 2612.476695]  [<ffffffffa034e3da>] btrfs_put_super+0x19/0x1b [btrfs]
[ 2612.477911]  [<ffffffff81153e53>] generic_shutdown_super+0x73/0xef
[ 2612.479106]  [<ffffffff811540e2>] kill_anon_super+0x13/0x1e
[ 2612.480226]  [<ffffffffa034e1e3>] btrfs_kill_super+0x17/0x23 [btrfs]
[ 2612.481471]  [<ffffffff81154307>] deactivate_locked_super+0x3b/0x50
[ 2612.482686]  [<ffffffff811547a7>] deactivate_super+0x3f/0x43
[ 2612.483791]  [<ffffffff8116b3ed>] cleanup_mnt+0x59/0x78
[ 2612.484842]  [<ffffffff8116b44c>] __cleanup_mnt+0x12/0x14
[ 2612.485900]  [<ffffffff8105d019>] task_work_run+0x8f/0xbc
[ 2612.486960]  [<ffffffff810028d8>] do_notify_resume+0x5a/0x6b
[ 2612.488083]  [<ffffffff81236e5b>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 2612.489333]  [<ffffffff8142a17f>] int_signal+0x12/0x17
[ 2612.490353] ---[ end trace 54a960a6bdcb8d93 ]---
[ 2612.557253] VFS: Busy inodes after unmount of sdb. Self-destruct in 5 seconds.  Have a nice day...

Kmemleak confirmed the ordered extent leak (and btrfs inode specific
structures such as delayed nodes):

$ cat /sys/kernel/debug/kmemleak
unreferenced object 0xffff880154290db0 (size 576):
  comm "btrfsck", pid 21980, jiffies 4295542503 (age 1273.412s)
  hex dump (first 32 bytes):
    01 40 00 00 01 00 00 00 b0 1d f1 4e 01 88 ff ff  [email protected]....
    00 00 00 00 00 00 00 00 c8 0d 29 54 01 88 ff ff  ..........)T....
  backtrace:
    [<ffffffff8141d74d>] kmemleak_update_trace+0x4c/0x6a
    [<ffffffff8122f2c0>] radix_tree_node_alloc+0x6d/0x83
    [<ffffffff8122fb26>] __radix_tree_create+0x109/0x190
    [<ffffffff8122fbdd>] radix_tree_insert+0x30/0xac
    [<ffffffffa03b9bde>] btrfs_get_or_create_delayed_node+0x130/0x187 [btrfs]
    [<ffffffffa03bb82d>] btrfs_delayed_delete_inode_ref+0x32/0xac [btrfs]
    [<ffffffffa0379dae>] __btrfs_unlink_inode+0xee/0x288 [btrfs]
    [<ffffffffa037c715>] btrfs_unlink_inode+0x1e/0x40 [btrfs]
    [<ffffffffa037c797>] btrfs_unlink+0x60/0x9b [btrfs]
    [<ffffffff8115d7f0>] vfs_unlink+0x9c/0xed
    [<ffffffff8115f5de>] do_unlinkat+0x12c/0x1fa
    [<ffffffff811601a7>] SyS_unlinkat+0x29/0x2b
    [<ffffffff81429e92>] system_call_fastpath+0x12/0x17
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff88014ef11db0 (size 576):
  comm "rm", pid 22009, jiffies 4295542593 (age 1273.052s)
  hex dump (first 32 bytes):
    02 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 c8 1d f1 4e 01 88 ff ff  ...........N....
  backtrace:
    [<ffffffff8141d74d>] kmemleak_update_trace+0x4c/0x6a
    [<ffffffff8122f2c0>] radix_tree_node_alloc+0x6d/0x83
    [<ffffffff8122fb26>] __radix_tree_create+0x109/0x190
    [<ffffffff8122fbdd>] radix_tree_insert+0x30/0xac
    [<ffffffffa03b9bde>] btrfs_get_or_create_delayed_node+0x130/0x187 [btrfs]
    [<ffffffffa03bb82d>] btrfs_delayed_delete_inode_ref+0x32/0xac [btrfs]
    [<ffffffffa0379dae>] __btrfs_unlink_inode+0xee/0x288 [btrfs]
    [<ffffffffa037c715>] btrfs_unlink_inode+0x1e/0x40 [btrfs]
    [<ffffffffa037c797>] btrfs_unlink+0x60/0x9b [btrfs]
    [<ffffffff8115d7f0>] vfs_unlink+0x9c/0xed
    [<ffffffff8115f5de>] do_unlinkat+0x12c/0x1fa
    [<ffffffff811601a7>] SyS_unlinkat+0x29/0x2b
    [<ffffffff81429e92>] system_call_fastpath+0x12/0x17
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff8800336feda8 (size 584):
  comm "aio-stress", pid 22031, jiffies 4295543006 (age 1271.400s)
  hex dump (first 32 bytes):
    00 40 3e 00 00 00 00 00 00 00 8f 42 00 00 00 00  .@>........B....
    00 00 01 00 00 00 00 00 00 00 01 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8114eb34>] create_object+0x172/0x29a
    [<ffffffff8141d790>] kmemleak_alloc+0x25/0x41
    [<ffffffff81141ae6>] kmemleak_alloc_recursive.constprop.52+0x16/0x18
    [<ffffffff81145288>] kmem_cache_alloc+0xf7/0x198
    [<ffffffffa0389243>] __btrfs_add_ordered_extent+0x43/0x309 [btrfs]
    [<ffffffffa038968b>] btrfs_add_ordered_extent_dio+0x12/0x14 [btrfs]
    [<ffffffffa03810e2>] btrfs_get_blocks_direct+0x3ef/0x571 [btrfs]
    [<ffffffff81181349>] do_blockdev_direct_IO+0x62a/0xb47
    [<ffffffff8118189a>] __blockdev_direct_IO+0x34/0x36
    [<ffffffffa03776e5>] btrfs_direct_IO+0x16a/0x1e8 [btrfs]
    [<ffffffff81100373>] generic_file_direct_write+0xb8/0x12d
    [<ffffffffa038615c>] btrfs_file_write_iter+0x24b/0x42f [btrfs]
    [<ffffffff8118bb0d>] aio_run_iocb+0x2b7/0x32e
    [<ffffffff8118c99a>] do_io_submit+0x26e/0x2ff
    [<ffffffff8118ca3b>] SyS_io_submit+0x10/0x12
    [<ffffffff81429e92>] system_call_fastpath+0x12/0x17

CC: <[email protected]> # 3.19, 3.18 and 3.17
Signed-off-by: Filipe Manana <[email protected]>
Signed-off-by: Chris Mason <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Passing zeroed drm_radeon_cs struct to DRM_IOCTL_RADEON_CS produces the
following oops.

Fix by always calling INIT_LIST_HEAD() to avoid the crash in list_sort().

----------------------------------

 #include <stdint.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <sys/ioctl.h>
 #include <drm/radeon_drm.h>

 static const struct drm_radeon_cs cs;

 int main(int argc, char **argv)
 {
         return ioctl(open(argv[1], O_RDWR), DRM_IOCTL_RADEON_CS, &cs);
 }

----------------------------------

[ttrantal@test2 ~]$ ./main /dev/dri/card0
[   46.904650] BUG: unable to handle kernel NULL pointer dereference at           (null)
[   46.905022] IP: [<ffffffff814d6df2>] list_sort+0x42/0x240
[   46.905022] PGD 68f29067 PUD 688b5067 PMD 0
[   46.905022] Oops: 0002 [#1] SMP
[   46.905022] CPU: 0 PID: 2413 Comm: main Not tainted 4.0.0-rc1+ #58
[   46.905022] Hardware name: Hewlett-Packard HP Compaq dc5750 Small Form Factor/0A64h, BIOS 786E3 v02.10 01/25/2007
[   46.905022] task: ffff880058e2bcc0 ti: ffff880058e64000 task.ti: ffff880058e64000
[   46.905022] RIP: 0010:[<ffffffff814d6df2>]  [<ffffffff814d6df2>] list_sort+0x42/0x240
[   46.905022] RSP: 0018:ffff880058e67998  EFLAGS: 00010246
[   46.905022] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   46.905022] RDX: ffffffff81644410 RSI: ffff880058e67b40 RDI: ffff880058e67a58
[   46.905022] RBP: ffff880058e67a88 R08: 0000000000000000 R09: 0000000000000000
[   46.905022] R10: ffff880058e2bcc0 R11: ffffffff828e6ca0 R12: ffffffff81644410
[   46.905022] R13: ffff8800694b8018 R14: 0000000000000000 R15: ffff880058e679b0
[   46.905022] FS:  00007fdc65a65700(0000) GS:ffff88006d600000(0000) knlGS:0000000000000000
[   46.905022] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   46.905022] CR2: 0000000000000000 CR3: 0000000058dd9000 CR4: 00000000000006f0
[   46.905022] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   46.905022] DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
[   46.905022] Stack:
[   46.905022]  ffff880058e67b40 ffff880058e2bcc0 ffff880058e67a78 0000000000000000
[   46.905022]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   46.905022]  0000000000000000 0000000000000000 0000000000000000 0000000000000000
[   46.905022] Call Trace:
[   46.905022]  [<ffffffff81644a65>] radeon_cs_parser_fini+0x195/0x220
[   46.905022]  [<ffffffff81645069>] radeon_cs_ioctl+0xa9/0x960
[   46.905022]  [<ffffffff815e1f7c>] drm_ioctl+0x19c/0x640
[   46.905022]  [<ffffffff810f8fdd>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[   46.905022]  [<ffffffff810f90ad>] ? trace_hardirqs_on+0xd/0x10
[   46.905022]  [<ffffffff8160c066>] radeon_drm_ioctl+0x46/0x80
[   46.905022]  [<ffffffff81211868>] do_vfs_ioctl+0x318/0x570
[   46.905022]  [<ffffffff81462ef6>] ? selinux_file_ioctl+0x56/0x110
[   46.905022]  [<ffffffff81211b41>] SyS_ioctl+0x81/0xa0
[   46.905022]  [<ffffffff81dc6312>] system_call_fastpath+0x12/0x17
[   46.905022] Code: 48 89 b5 10 ff ff ff 0f 84 03 01 00 00 4c 8d bd 28 ff ff
ff 31 c0 48 89 fb b9 15 00 00 00 49 89 d4 4c 89 ff f3 48 ab 48 8b 46 08 <48> c7
00 00 00 00 00 48 8b 0e 48 85 c9 0f 84 7d 00 00 00 c7 85
[   46.905022] RIP  [<ffffffff814d6df2>] list_sort+0x42/0x240
[   46.905022]  RSP <ffff880058e67998>
[   46.905022] CR2: 0000000000000000
[   47.149253] ---[ end trace 09576b4e8b2c20b8 ]---

Reviewed-by: Christian König <[email protected]>
Signed-off-by: Tommi Rantala <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
Cc: [email protected]
anholt pushed a commit that referenced this pull request Apr 21, 2015
Under z/VM PQAP might trigger an operation exception if no crypto cards
are defined via APVIRTUAL or APDEDICATED.

[  386.098666] Kernel BUG at 0000000000135c56 [verbose debug info unavailable]
[  386.098693] illegal operation: 0001 ilc:2 [#1] SMP
[...]
[  386.098751] Krnl PSW : 0704c00180000000 0000000000135c56 (kvm_s390_apxa_installed+0x46/0x98)
[...]
[  386.098804]  [<000000000013627c>] kvm_arch_init_vm+0x29c/0x358
[  386.098806]  [<000000000012d008>] kvm_dev_ioctl+0xc0/0x460
[  386.098809]  [<00000000002c639a>] do_vfs_ioctl+0x332/0x508
[  386.098811]  [<00000000002c660e>] SyS_ioctl+0x9e/0xb0
[  386.098814]  [<000000000070476a>] system_call+0xd6/0x258
[  386.098815]  [<000003fffc7400a2>] 0x3fffc7400a2

Lets add an extable entry and provide a zeroed config in that case.

Reported-by: Stefan Zimmermann <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>
Reviewed-by: Thomas Huth <[email protected]>
Tested-by: Stefan Zimmermann <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
When do suspend/resume stress test, some log shows "rcv is not +last".
The issue is that enet suspend will disable phy clock, phy link down,
after resume back, enet MAC redo initial and ready to tx/rx packet,
but phy still is not ready which is doing auto-negotiation. When phy
link is not up, don't schdule napi soft irq.

[Peter]
It has fixed kernel panic after long time suspend/resume test
with nfs rootfs.

[ 8864.429458] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.434799] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.440088] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.445424] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.450782] fec 2188000.ethernet eth0: rcv is not +last
[ 8864.456111] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 8864.464225] pgd = 80004000
[ 8864.466997] [00000000] *pgd=00000000
[ 8864.470627] Internal error: Oops: 17 [#1] SMP ARM
[ 8864.475353] Modules linked in: evbug
[ 8864.479006] CPU: 0 PID: 3 Comm: ksoftirqd/0 Not tainted 4.0.0-rc1-00044-g7a2a1d2 raspberrypi#234
[ 8864.486854] Hardware name: Freescale i.MX6 SoloX (Device Tree)
[ 8864.492709] task: be069380 ti: be07a000 task.ti: be07a000
[ 8864.498137] PC is at memcpy+0x80/0x330
[ 8864.501919] LR is at gro_pull_from_frag0+0x34/0xa8
[ 8864.506735] pc : [<802bb080>]    lr : [<8057c204>]    psr: 00000113
[ 8864.506735] sp : be07bbd4  ip : 00000010  fp : be07bc0c
[ 8864.518235] r10: 0000000e  r9 : 00000000  r8 : 809c7754
[ 8864.523479] r7 : 809c7754  r6 : bb43c040  r5 : bd280cc0  r4 : 00000012
[ 8864.530025] r3 : 00000804  r2 : fffffff2  r1 : 00000000  r0 : bb43b83c
[ 8864.536575] Flags: nzcv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[ 8864.543904] Control: 10c5387d  Table: bd14c04a  DAC: 00000015
[ 8864.549669] Process ksoftirqd/0 (pid: 3, stack limit = 0xbe07a210)
[ 8864.555869] Stack: (0xbe07bbd4 to 0xbe07c000)
[ 8864.560250] bbc0:                                              bd280cc0 bb43c040 809c7754
[ 8864.568455] bbe0: 809c7754 bb43b83c 00000012 8057c204 00000000 bd280cc0 bd8a0718 00000003
[ 8864.576658] bc00: be07bc5c be07bc10 8057ebf0 8057c1dc 00000000 00000000 8057ecc4 bef59760
[ 8864.584863] bc20: 00000002 bd8a0000 be07bc64 809c7754 00000000 bd8a0718 bd280cc0 bd8a0000
[ 8864.593066] bc40: 00000000 0000001c 00000000 bd8a0000 be07bc74 be07bc60 8057f148 8057eb90
[ 8864.601268] bc60: bf0810a0 00000000 be07bcf4 be07bc78 8044e7b4 8057f12c 00000000 8007df6c
[ 8864.609470] bc80: bd8a0718 00000040 00000000 bd280a80 00000002 00000019 bd8a0600 bd8a1214
[ 8864.617672] bca0: bd8a0690 bf0810a0 00000000 00000000 bd8a1000 00000000 00000027 bd280cc0
[ 8864.625874] bcc0: 80062708 800625cc 000943db bd8a0718 00000001 000d1166 00000040 be7c1ec0
[ 8864.634077] bce0: 0000012c be07bd00 be07bd3c be07bcf8 8057fc98 8044e3ac 809c2ec0 3ddff000
[ 8864.642280] bd00: be07bd00 be07bd00 be07bd08 be07bd08 00000000 00000020 809c608c 00000003
[ 8864.650481] bd20: 809c6080 40000001 809c6088 00200100 be07bd84 be07bd40 8002e690 8057fac8
[ 8864.658684] bd40: be07bd64 be07bd50 00000001 04208040 000d1165 0000000a be07bd84 809c0d7c
[ 8864.666885] bd60: 00000000 809c6af8 00000000 00000001 be008000 00000000 be07bd9c be07bd88
[ 8864.675087] bd80: 8002eb64 8002e564 00000125 809c0d7c be07bdc4 be07bda0 8006f100 8002eaac
[ 8864.683291] bda0: c080e10c be07bde8 809c6c6c c080e100 00000002 00000000 be07bde4 be07bdc8
[ 8864.691492] bdc0: 800087a0 8006f098 806f2934 20000013 ffffffff be07be1c be07be44 be07bde8
[ 8864.699695] bde0: 800133a4 80008784 00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.707896] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.716098] be20: 8006278c 806f2934 20000013 ffffffff be069380 be7c1680 be07be7c be07be48
[ 8864.724300] be40: 80049cfc 806f2910 00000001 00000000 80049cb4 00000000 be07be7c be7c1680
[ 8864.732502] be60: be3289c0 be069380 bd23b600 be0cfe00 be07bebc be07be80 806ed614 80049c68
[ 8864.740706] be80: be07a000 0000020a 809c608c 00000003 00000001 8002e858 be07a000 be035740
[ 8864.748907] bea0: 00000000 00000001 809d4598 00000000 be07bed4 be07bec0 806edd0c 806ed440
[ 8864.757110] bec0: be07a000 be07a000 be07bee4 be07bed8 806edd68 806edcf0 be07bef4 be07bee8
[ 8864.765311] bee0: 8002e860 806edd34 be07bf24 be07bef8 800494b0 8002e828 be069380 00000000
[ 8864.773512] bf00: be035780 be035740 8004938c 00000000 00000000 00000000 be07bfac be07bf28
[ 8864.781715] bf20: 80045928 80049398 be07bf44 00000001 00000000 be035740 00000000 00030003
[ 8864.789917] bf40: dead4ead ffffffff ffffffff 80a2716c 80b59b00 00000000 8088c954 be07bf5c
[ 8864.798120] bf60: be07bf5c 00000000 00000000 dead4ead ffffffff ffffffff 80a2716c 00000000
[ 8864.806320] bf80: 00000000 8088c954 be07bf88 be07bf88 be035780 8004584c 00000000 00000000
[ 8864.814523] bfa0: 00000000 be07bfb0 8000ed10 80045858 00000000 00000000 00000000 00000000
[ 8864.822723] bfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 8864.830925] bfe0: 00000000 00000000 00000000 00000000 00000013 00000000 5ffbb5f7 f9fcf5e7
[ 8864.839115] Backtrace:
[ 8864.841631] [<8057c1d0>] (gro_pull_from_frag0) from [<8057ebf0>] (dev_gro_receive+0x6c/0x3f8)
[ 8864.850173]  r6:00000003 r5:bd8a0718 r4:bd280cc0 r3:00000000
[ 8864.855958] [<8057eb84>] (dev_gro_receive) from [<8057f148>] (napi_gro_receive+0x28/0xac)
[ 8864.864152]  r10:bd8a0000 r9:00000000 r8:0000001c r7:00000000 r6:bd8a0000 r5:bd280cc0
[ 8864.872115]  r4:bd8a0718
[ 8864.874713] [<8057f120>] (napi_gro_receive) from [<8044e7b4>] (fec_enet_rx_napi+0x414/0xc74)
[ 8864.883167]  r5:00000000 r4:bf0810a0
[ 8864.886823] [<8044e3a0>] (fec_enet_rx_napi) from [<8057fc98>] (net_rx_action+0x1dc/0x2ec)
[ 8864.895016]  r10:be07bd00 r9:0000012c r8:be7c1ec0 r7:00000040 r6:000d1166 r5:00000001
[ 8864.902982]  r4:bd8a0718
[ 8864.905570] [<8057fabc>] (net_rx_action) from [<8002e690>] (__do_softirq+0x138/0x2c4)
[ 8864.913417]  r10:00200100 r9:809c6088 r8:40000001 r7:809c6080 r6:00000003 r5:809c608c
[ 8864.921382]  r4:00000020
[ 8864.923966] [<8002e558>] (__do_softirq) from [<8002eb64>] (irq_exit+0xc4/0x138)
[ 8864.931289]  r10:00000000 r9:be008000 r8:00000001 r7:00000000 r6:809c6af8 r5:00000000
[ 8864.939252]  r4:809c0d7c
[ 8864.941841] [<8002eaa0>] (irq_exit) from [<8006f100>] (__handle_domain_irq+0x74/0xe8)
[ 8864.949688]  r4:809c0d7c r3:00000125
[ 8864.953342] [<8006f08c>] (__handle_domain_irq) from [<800087a0>] (gic_handle_irq+0x28/0x68)
[ 8864.961707]  r9:00000000 r8:00000002 r7:c080e100 r6:809c6c6c r5:be07bde8 r4:c080e10c
[ 8864.969597] [<80008778>] (gic_handle_irq) from [<800133a4>] (__irq_svc+0x44/0x5c)
[ 8864.977097] Exception stack(0xbe07bde8 to 0xbe07be30)
[ 8864.982173] bde0:                   00000001 00000001 00000000 00000000 be7c1680 00000000
[ 8864.990377] be00: be0cfe00 bd93eb40 00000002 00000000 00000000 be07be44 be07be00 be07be30
[ 8864.998573] be20: 8006278c 806f2934 20000013 ffffffff
[ 8865.003638]  r7:be07be1c r6:ffffffff r5:20000013 r4:806f2934
[ 8865.009447] [<806f2904>] (_raw_spin_unlock_irq) from [<80049cfc>] (finish_task_switch+0xa0/0x160)
[ 8865.018334]  r4:be7c1680 r3:be069380
[ 8865.021993] [<80049c5c>] (finish_task_switch) from [<806ed614>] (__schedule+0x1e0/0x5dc)
[ 8865.030098]  r8:be0cfe00 r7:bd23b600 r6:be069380 r5:be3289c0 r4:be7c1680
[ 8865.036942] [<806ed434>] (__schedule) from [<806edd0c>] (preempt_schedule_common+0x28/0x44)
[ 8865.045307]  r9:00000000 r8:809d4598 r7:00000001 r6:00000000 r5:be035740 r4:be07a000
[ 8865.053197] [<806edce4>] (preempt_schedule_common) from [<806edd68>] (_cond_resched+0x40/0x48)
[ 8865.061822]  r4:be07a000 r3:be07a000
[ 8865.065472] [<806edd28>] (_cond_resched) from [<8002e860>] (run_ksoftirqd+0x44/0x64)
[ 8865.073252] [<8002e81c>] (run_ksoftirqd) from [<800494b0>] (smpboot_thread_fn+0x124/0x190)
[ 8865.081550] [<8004938c>] (smpboot_thread_fn) from [<80045928>] (kthread+0xdc/0xf8)
[ 8865.089133]  r10:00000000 r9:00000000 r8:00000000 r7:8004938c r6:be035740 r5:be035780
[ 8865.097097]  r4:00000000 r3:be069380
[ 8865.100752] [<8004584c>] (kthread) from [<8000ed10>] (ret_from_fork+0x14/0x24)
[ 8865.107990]  r7:00000000 r6:00000000 r5:8004584c r4:be035780
[ 8865.113767] Code: e320f000 e4913004 e4914004 e4915004 (e4916004)
[ 8865.120006] ---[ end trace b0a4c6bd499288ca ]---
[ 8865.124697] Kernel panic - not syncing: Fatal exception in interrupt
[ 8865.131084] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

Cc: [v3.19+] [email protected]
Tested-by: Peter Chen <[email protected]>
Signed-off-by: Peter Chen <[email protected]>
Signed-off-by: Fugang Duan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
The a80 optimus has 8 CPUs. I propose we increase the maximum number of CPUs to 8 to avoid the following warning identified during automated boot testing [1].

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at ../arch/arm/kernel/devtree.c:144 arm_dt_init_cpu_maps+0x110/0x1e0()
DT /cpu 5 nodes greater than max cores 4, capping them
CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-00528-gbdccc4edeb03 #1
Hardware name: Allwinner sun9i Family
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0x74/0x90)
[] (dump_stack) from [] (warn_slowpath_common+0x70/0xac)
[] (warn_slowpath_common) from [] (warn_slowpath_fmt+0x30/0x40)
[] (warn_slowpath_fmt) from [] (arm_dt_init_cpu_maps+0x110/0x1e0)
[] (arm_dt_init_cpu_maps) from [] (setup_arch+0x634/0x8d4)
[] (setup_arch) from [] (start_kernel+0x88/0x3ac)
[] (start_kernel) from [<20008074>] (0x20008074)
---[ end trace cb88537fdc8fa200 ]---

[1] http://storage.kernelci.org/mainline/v3.19-528-gbdccc4edeb03/arm-sunxi_defconfig/lab-tbaker/boot-sun9i-a80-optimus.html

Cc: Maxime Ripard <[email protected]>
Cc: Olof Johansson <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Tyler Baker <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
…s to 16

The HiSilicon HiP04 has 16 CPUs. I propose we increase the maximum number of CPUs to 16 to avoid the following warning identified during automated boot testing [1].

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at ../arch/arm/kernel/devtree.c:144 arm_dt_init_cpu_maps+0x118/0x1e8()
DT /cpu 9 nodes greater than max cores 8, capping them
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-00528-gbdccc4edeb03 #1
Hardware name: Hisilicon HiP04 (Flattened Device Tree)
[] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[] (show_stack) from [] (dump_stack+0x78/0x94)
[] (dump_stack) from [] (warn_slowpath_common+0x74/0xb0)
[] (warn_slowpath_common) from [] (warn_slowpath_fmt+0x30/0x40)
[] (warn_slowpath_fmt) from [] (arm_dt_init_cpu_maps+0x118/0x1e8)
[] (arm_dt_init_cpu_maps) from [] (setup_arch+0x638/0x9a0)
[] (setup_arch) from [] (start_kernel+0x8c/0x3b4)
[] (start_kernel) from [<10208074>] (0x10208074)
---[ end trace cb88537fdc8fa200 ]---

[1] http://storage.kernelci.org/mainline/v3.19-528-gbdccc4edeb03/arm-multi_v7_defconfig/lab-tbaker/boot-hip04-d01.html

Cc: Olof Johansson <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Signed-off-by: Tyler Baker <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
The commit below introduced an unsafe dereference of
mvmvif->phy_ctxt. It can be NULL even if we hold the mutex.
We can be handling a BT Coex notification while the vif has
already been unassigned. This can happen since the BT Coex
notification is hanled asynchronuously: we can have started
to handle the BT Coex notification trying to acquire the
mutex while the unassign flow already got it. The BT Coex
notification handling will wait for the mutext. I'll get it
later, but then mvmvif->phy_ctxt will be NULL.

Panic log:

BUG: unable to handle kernel NULL pointer dereference at   (null)
IP: [<f985180d>] iwl_mvm_bt_notif_iterator+0x9d/0x340 [iwlmvm]
*pdpt = 0000000000000000 *pde = f000eef300000007
Oops: 0000 [#1] SMP
Workqueue: events iwl_mvm_async_handlers_wk [iwlmvm]
task: ed719b20 ti: ec03e000 task.ti: ec03e000
EIP: 0060:[<f985180d>] EFLAGS: 00010202 CPU: 2
EIP is at iwl_mvm_bt_notif_iterator+0x9d/0x340 [iwlmvm]
EAX: 00000000 EBX: f6d3cb70 ECX: f6d3cb70 EDX: 00000000
ESI: ec03fe40 EDI: efeb8810 EBP: ec03fdf0 ESP: ec03fdac
 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
CR0: 80050033 CR2: 00000000 CR3: 01a1a000 CR4: 001407f0
Stack:
 f743ca80 f744a404 ec03fdcc c10e3952 00003aba f743ca80 00000246 f743ca80
 00000246 00000000 00000001 00000000 ebd45ff6 ebd458a4 f6d3c500 ebd45578
 ebd44b01 ec03fe18 f99e1bc2 00000002 ebd44bc0 f9851770 00000000 f6d3c500
Call Trace:
 [<c10e3952>] ? ring_buffer_unlock_commit+0xa2/0xd0
 [<f99e1bc2>] __iterate_interfaces+0x82/0x110 [mac80211]
 [<f9851770>] ? iwl_mvm_bt_coex_reduced_txp+0x140/0x140 [iwlmvm]
 [<f99e1c6a>] ieee80211_iterate_active_interfaces_atomic+0x1a/0x20 [mac80211]
 [<f9851427>] iwl_mvm_bt_coex_notif_handle+0x77/0x280 [iwlmvm]
 [<f9852161>] iwl_mvm_rx_bt_coex_notif_old+0x211/0x220 [iwlmvm]
 [<f9850b8b>] iwl_mvm_rx_bt_coex_notif+0x19b/0x1b0 [iwlmvm]
 [<f983944f>] iwl_mvm_async_handlers_wk+0x7f/0xe0 [iwlmvm]

CC: <[email protected]> [3.19+]
Fixes: 123f515 ("iwlwifi: mvm: BT Coex - add support for TTC / RRC")
Signed-off-by: Emmanuel Grumbach <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Commit de7b5b3 ("net: eth: xgene: change APM X-Gene SoC platform
ethernet to support ACPI") breaks booting with devicetree with UEFI
firmware. In that case, I get:

Unhandled fault: synchronous external abort (0x96000010) at 0xfffffc0000620010
 Internal error: : 96000010 [#1] SMP
 Modules linked in: vfat fat xfs libcrc32c ahci_xgene libahci_platform libahci
 CPU: 7 PID: 634 Comm: NetworkManager Not tainted 4.0.0-rc1+ #4
 Hardware name: AppliedMicro Mustang/Mustang, BIOS 1.1.0-rh-0.14 Mar  1 2015
 task: fffffe03d4c7e100 ti: fffffe03d4e24000 task.ti: fffffe03d4e24000
 PC is at xgene_enet_rd_mcx_mac.isra.11+0x58/0xd4
 LR is at xgene_gmac_tx_enable+0x2c/0x50
 pc : [<fffffe000069d6fc>] lr : [<fffffe000069dcc4>] pstate: 80000145
 sp : fffffe03d4e27590
 x29: fffffe03d4e27590 x28: 0000000000000000
 x27: fffffe03d4e277c0 x26: fffffe03da8fda10
 x25: fffffe03d4e2760c x24: fffffe03d49e28c0
 x23: fffffc0000620004 x22: 0000000000000000
 x21: fffffc0000620000 x20: fffffc0000620010
 x19: 000000000000000b x18: 000003ffd4a96020
 x17: 000003ff7fc1f7a0 x16: fffffe000079b9cc
 x15: 0000000000000000 x14: 0000000000000000
 x13: 0000000000000000 x12: fffffe03d4e24000
 x11: fffffe03d4e27da0 x10: 0000000000000001
 x9 : 0000000000000000 x8 : fffffe03d4e27a20
 x7 : 0000000000000000 x6 : 00000000ffffffef
 x5 : fffffe000105f7d0 x4 : fffffe00007ca8c8
 x3 : fffffe03d4e2760c x2 : 0000000000000000
 x1 : fffffc0000620000 x0 : 0000000040000000

 Process NetworkManager (pid: 634, stack limit = 0xfffffe03d4e24028)
 Stack: (0xfffffe03d4e27590 to 0xfffffe03d4e28000)
 ...
 Call trace:
 [<fffffe000069d6fc>] xgene_enet_rd_mcx_mac.isra.11+0x58/0xd4
 [<fffffe000069dcc0>] xgene_gmac_tx_enable+0x28/0x50
 [<fffffe00006a112c>] xgene_enet_open+0x2c/0x130
 [<fffffe00007b9254>] __dev_open+0xc8/0x148
 [<fffffe00007b956c>] __dev_change_flags+0x90/0x158
 [<fffffe00007b9664>] dev_change_flags+0x30/0x70
 [<fffffe00007c8ab8>] do_setlink+0x278/0x870
 [<fffffe00007c95bc>] rtnl_newlink+0x404/0x6a8
 [<fffffe00007c8040>] rtnetlink_rcv_msg+0x98/0x218
 [<fffffe00007e78e4>] netlink_rcv_skb+0xe0/0xf8
 [<fffffe00007c7f94>] rtnetlink_rcv+0x30/0x44
 [<fffffe00007e6f2c>] netlink_unicast+0xfc/0x210
 [<fffffe00007e75b8>] netlink_sendmsg+0x498/0x5ac
 [<fffffe00007990b8>] do_sock_sendmsg+0xa4/0xcc
 [<fffffe000079a958>] ___sys_sendmsg+0x1fc/0x208
 [<fffffe000079b984>] __sys_sendmsg+0x4c/0x94
 [<fffffe000079b9f8>] SyS_sendmsg+0x2c/0x3c

The problem here is that the enet hw clocks are not getting
initialized because of a test to avoid the initialization if
UEFI is used to boot. This is an incorrect test. When booting
with UEFI and devicetree, the kernel must still initialize
the enet hw clocks. If booting with ACPI, the clock hw is
not exposed to the kernel and it is that case where we want
to avoid initializing clocks.

Signed-off-by: Mark Salter <[email protected]>
Acked-by: Feng Kan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
This crash was reported:

[  366.947370] sd 3:0:1:0: [sdb] Spinning up disk....
[  368.804046] BUG: unable to handle kernel NULL pointer dereference at           (null)
[  368.804072] IP: [<ffffffff81358457>] __mutex_lock_common.isra.7+0x9c/0x15b
[  368.804098] PGD 0
[  368.804114] Oops: 0002 [#1] SMP
[  368.804143] CPU 1
[  368.804151] Modules linked in: sg netconsole s3g(PO) uinput joydev hid_multitouch usbhid hid snd_hda_codec_via cpufreq_userspace cpufreq_powersave cpufreq_stats uhci_hcd cpufreq_conservative snd_hda_intel snd_hda_codec snd_hwdep snd_pcm sdhci_pci snd_page_alloc sdhci snd_timer snd psmouse evdev serio_raw pcspkr soundcore xhci_hcd shpchp s3g_drm(O) mvsas mmc_core ahci libahci drm i2c_core acpi_cpufreq mperf video processor button thermal_sys dm_dmirror exfat_fs exfat_core dm_zcache dm_mod padlock_aes aes_generic padlock_sha iscsi_target_mod target_core_mod configfs sswipe libsas libata scsi_transport_sas picdev via_cputemp hwmon_vid fuse parport_pc ppdev lp parport autofs4 ext4 crc16 mbcache jbd2 sd_mod crc_t10dif usb_storage scsi_mod ehci_hcd usbcore usb_common
[  368.804749]
[  368.804764] Pid: 392, comm: kworker/u:3 Tainted: P        W  O 3.4.87-logicube-ng.22 #1 To be filled by O.E.M. To be filled by O.E.M./EPIA-M920
[  368.804802] RIP: 0010:[<ffffffff81358457>]  [<ffffffff81358457>] __mutex_lock_common.isra.7+0x9c/0x15b
[  368.804827] RSP: 0018:ffff880117001cc0  EFLAGS: 00010246
[  368.804842] RAX: 0000000000000000 RBX: ffff8801185030d0 RCX: ffff88008edcb420
[  368.804857] RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff8801185030d4
[  368.804873] RBP: ffff8801181531c0 R08: 0000000000000020 R09: 00000000fffffffe
[  368.804885] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801185030d4
[  368.804899] R13: 0000000000000002 R14: ffff880117001fd8 R15: ffff8801185030d8
[  368.804916] FS:  0000000000000000(0000) GS:ffff88011fc80000(0000) knlGS:0000000000000000
[  368.804931] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  368.804946] CR2: 0000000000000000 CR3: 000000000160b000 CR4: 00000000000006e0
[  368.804962] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  368.804978] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  368.804995] Process kworker/u:3 (pid: 392, threadinfo ffff880117000000, task ffff8801181531c0)
[  368.805009] Stack:
[  368.805017]  ffff8801185030d8 0000000000000000 ffffffff8161ddf0 ffffffff81056f7c
[  368.805062]  000000000000b503 ffff8801185030d0 ffff880118503000 0000000000000000
[  368.805100]  ffff8801185030d0 ffff8801188b8000 ffff88008edcb420 ffffffff813583ac
[  368.805135] Call Trace:
[  368.805153]  [<ffffffff81056f7c>] ? up+0xb/0x33
[  368.805168]  [<ffffffff813583ac>] ? mutex_lock+0x16/0x25
[  368.805194]  [<ffffffffa018c414>] ? smp_execute_task+0x4e/0x222 [libsas]
[  368.805217]  [<ffffffffa018ce1c>] ? sas_find_bcast_dev+0x3c/0x15d [libsas]
[  368.805240]  [<ffffffffa018ce4f>] ? sas_find_bcast_dev+0x6f/0x15d [libsas]
[  368.805264]  [<ffffffffa018e989>] ? sas_ex_revalidate_domain+0x37/0x2ec [libsas]
[  368.805280]  [<ffffffff81355a2a>] ? printk+0x43/0x48
[  368.805296]  [<ffffffff81359a65>] ? _raw_spin_unlock_irqrestore+0xc/0xd
[  368.805318]  [<ffffffffa018b767>] ? sas_revalidate_domain+0x85/0xb6 [libsas]
[  368.805336]  [<ffffffff8104e5d9>] ? process_one_work+0x151/0x27c
[  368.805351]  [<ffffffff8104f6cd>] ? worker_thread+0xbb/0x152
[  368.805366]  [<ffffffff8104f612>] ? manage_workers.isra.29+0x163/0x163
[  368.805382]  [<ffffffff81052c4e>] ? kthread+0x79/0x81
[  368.805399]  [<ffffffff8135fea4>] ? kernel_thread_helper+0x4/0x10
[  368.805416]  [<ffffffff81052bd5>] ? kthread_flush_work_fn+0x9/0x9
[  368.805431]  [<ffffffff8135fea0>] ? gs_change+0x13/0x13
[  368.805442] Code: 83 7d 30 63 7e 04 f3 90 eb ab 4c 8d 63 04 4c 8d 7b 08 4c 89 e7 e8 fa 15 00 00 48 8b 43 10 4c 89 3c 24 48 89 63 10 48 89 44 24 08 <48> 89 20 83 c8 ff 48 89 6c 24 10 87 03 ff c8 74 35 4d 89 ee 41
[  368.805851] RIP  [<ffffffff81358457>] __mutex_lock_common.isra.7+0x9c/0x15b
[  368.805877]  RSP <ffff880117001cc0>
[  368.805886] CR2: 0000000000000000
[  368.805899] ---[ end trace b720682065d8f4cc ]---

It's directly caused by 89d3cf6 [SCSI] libsas: add mutex for SMP task
execution, but shows a deeper cause: expander functions expect to be able to
cast to and treat domain devices as expanders.  The correct fix is to only do
expander discover when we know we've got an expander device to avoid wrongly
casting a non-expander device.

Reported-by: Praveen Murali <[email protected]>
Tested-by: Praveen Murali <[email protected]>
Cc: [email protected]
Signed-off-by: James Bottomley <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
We skip initialisation of ITS in case the device-tree has no
corresponding description, but we are still accessing to ITS bits while
setting CPU interface what leads to the kernel panic:

ITS: No ITS available, not enabling LPIs
CPU0: found redistributor 0 region 0:0x000000002f100000
Unable to handle kernel NULL pointer dereference at virtual address 00000000
pgd = ffffffc0007fb000
[00000000] *pgd=00000000fc407003, *pud=00000000fc407003, *pmd=00000000fc408003, *pte=006000002f000707
Internal error: Oops: 96000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.19.0-rc2+ raspberrypi#318
Hardware name: FVP Base (DT)
task: ffffffc00077edb0 ti: ffffffc00076c000 task.ti: ffffffc00076c000
PC is at its_cpu_init+0x2c/0x320
LR is at gic_cpu_init+0x168/0x1bc

It happens in gic_rdists_supports_plpis() because gic_rdists is NULL.
The gic_rdists is set to non-NULL only when ITS node is presented in
the device-tree.

Fix this by moving the call to gic_rdists_supports_plpis() inside the
!list_empty(&its_nodes) block, because it is that list that guards the
validity of the rest of the information in this driver.

Acked-by: Marc Zyngier <[email protected]>
Signed-off-by: Vladimir Murzin <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Jason Cooper <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
sysctl has sysctl.net.core.rmem_*/wmem_* parameters which can be
set to incorrect values. Given that 'struct sk_buff' allocates from
rcvbuf, incorrectly set buffer length could result to memory
allocation failures. For example, set them as follows:

    # sysctl net.core.rmem_default=64
      net.core.wmem_default = 64
    # sysctl net.core.wmem_default=64
      net.core.wmem_default = 64
    # ping localhost -s 1024 -i 0 > /dev/null

This could result to the following failure:

skbuff: skb_over_panic: text:ffffffff81628db4 len:-32 put:-32
head:ffff88003a1cc200 data:ffff88003a1cc200 tail:0xffffffe0 end:0xc0 dev:<NULL>
kernel BUG at net/core/skbuff.c:102!
invalid opcode: 0000 [#1] SMP
...
task: ffff88003b7f5550 ti: ffff88003ae88000 task.ti: ffff88003ae88000
RIP: 0010:[<ffffffff8155fbd1>]  [<ffffffff8155fbd1>] skb_put+0xa1/0xb0
RSP: 0018:ffff88003ae8bc68  EFLAGS: 00010296
RAX: 000000000000008d RBX: 00000000ffffffe0 RCX: 0000000000000000
RDX: ffff88003fdcf598 RSI: ffff88003fdcd9c8 RDI: ffff88003fdcd9c8
RBP: ffff88003ae8bc88 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 00000000000002b2 R12: 0000000000000000
R13: 0000000000000000 R14: ffff88003d3f7300 R15: ffff88000012a900
FS:  00007fa0e2b4a840(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000d0f7e0 CR3: 000000003b8fb000 CR4: 00000000000006f0
Stack:
 ffff88003a1cc200 00000000ffffffe0 00000000000000c0 ffffffff818cab1d
 ffff88003ae8bd68 ffffffff81628db4 ffff88003ae8bd48 ffff88003b7f5550
 ffff880031a09408 ffff88003b7f5550 ffff88000012aa48 ffff88000012ab00
Call Trace:
 [<ffffffff81628db4>] unix_stream_sendmsg+0x2c4/0x470
 [<ffffffff81556f56>] sock_write_iter+0x146/0x160
 [<ffffffff811d9612>] new_sync_write+0x92/0xd0
 [<ffffffff811d9cd6>] vfs_write+0xd6/0x180
 [<ffffffff811da499>] SyS_write+0x59/0xd0
 [<ffffffff81651532>] system_call_fastpath+0x12/0x17
Code: 00 00 48 89 44 24 10 8b 87 c8 00 00 00 48 89 44 24 08 48 8b 87 d8 00
      00 00 48 c7 c7 30 db 91 81 48 89 04 24 31 c0 e8 4f a8 0e 00 <0f> 0b
      eb fe 66 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 48 83
RIP  [<ffffffff8155fbd1>] skb_put+0xa1/0xb0
RSP <ffff88003ae8bc68>
Kernel panic - not syncing: Fatal exception

Moreover, the possible minimum is 1, so we can get another kernel panic:
...
BUG: unable to handle kernel paging request at ffff88013caee5c0
IP: [<ffffffff815604cf>] __alloc_skb+0x12f/0x1f0
...

Signed-off-by: Alexey Kodanev <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Functions rtsx_usb_ep0_read_register() and rtsx_usb_get_card_status()
both use arbitrary buffer addresses from arguments directly for DMA and
the buffers could be located in stack. This was caught by DMA-API debug
check.

Fixes this by using double-buffers via kzalloc in both functions to
guarantee the validity of DMA buffer.

WARNING: CPU: 1 PID: 25 at lib/dma-debug.c:1166 check_for_stack+0x96/0xe0()
ehci-pci 0000:00:1a.0: DMA-API: device driver maps memory from stack
[addr=ffff8801199e3cef]
Modules linked in: rtsx_usb_ms arc4 memstick intel_rapl iosf_mbi
rtl8192ce snd_hda_codec_hdmi snd_hda_codec_realtek
snd_hda_codec_generic snd_hda_intel rtl_pci rtl8192c_common
snd_hda_controller x86_pkg_temp_thermal snd_hda_codec rtlwifi mac80211
coretemp kvm_intel kvm iTCO_wdt snd_hwdep snd_seq snd_seq_device
crct10dif_pclmul iTCO_vendor_support sparse_keymap cfg80211
crc32_pclmul snd_pcm crc32c_intel ghash_clmulni_intel rfkill i2c_i801
snd_timer shpchp snd serio_raw mei_me lpc_ich soundcore mei tpm_tis
tpm wmi nfsd auth_rpcgss nfs_acl lockd grace sunrpc i915
rtsx_usb_sdmmc mmc_core 8021q uas garp stp i2c_algo_bit llc mrp
drm_kms_helper usb_storage drm rtsx_usb mfd_core r8169 mii video
CPU: 1 PID: 25 Comm: kworker/1:2 Not tainted 3.20.0-0.rc0.git7.3.fc22.x86_64 #1
Hardware name: WB WB-B06211/WB-B0621, BIOS EB062IWB V1.0 12/12/2013
Workqueue: events rtsx_usb_ms_handle_req [rtsx_usb_ms]
 0000000000000000 000000003d188e66 ffff8801199e3808 ffffffff8187642b
 0000000000000000 ffff8801199e3860 ffff8801199e3848 ffffffff810ab39a
 ffff8801199e3864 ffff8801199e3cef ffff880119b57098 ffff880119b37320
Call Trace:
 [<ffffffff8187642b>] dump_stack+0x4c/0x65
 [<ffffffff810ab39a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff810ab425>] warn_slowpath_fmt+0x55/0x70
 [<ffffffff8187efe6>] ? _raw_spin_unlock_irqrestore+0x36/0x70
 [<ffffffff81453156>] check_for_stack+0x96/0xe0
 [<ffffffff81453934>] debug_dma_map_page+0x104/0x150
 [<ffffffff81613b86>] usb_hcd_map_urb_for_dma+0x646/0x790
 [<ffffffff81614165>] usb_hcd_submit_urb+0x1d5/0xa90
 [<ffffffff81106f8f>] ? mark_held_locks+0x7f/0xc0
 [<ffffffff81106f8f>] ? mark_held_locks+0x7f/0xc0
 [<ffffffff81103a15>] ? lockdep_init_map+0x65/0x5d0
 [<ffffffff81615d7e>] usb_submit_urb+0x42e/0x5f0
 [<ffffffff81616787>] usb_start_wait_urb+0x77/0x190
 [<ffffffff8124f035>] ? __kmalloc+0x205/0x2d0
 [<ffffffff8161697c>] usb_control_msg+0xdc/0x130
 [<ffffffffa0031669>] rtsx_usb_ep0_read_register+0x59/0x70 [rtsx_usb]
 [<ffffffffa00310c1>] ? rtsx_usb_get_rsp+0x41/0x50 [rtsx_usb]
 [<ffffffffa071da4e>] rtsx_usb_ms_handle_req+0x7ce/0x9c5 [rtsx_usb_ms]

Reported-by: Josh Boyer <[email protected]>
Signed-off-by: Roger Tseng <[email protected]>
Signed-off-by: Lee Jones <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
We don't delete napi from hash list during module exit. This will
cause the following panic when doing module load and unload:

BUG: unable to handle kernel paging request at 0000004e00000075
IP: [<ffffffff816bd01b>] napi_hash_add+0x6b/0xf0
PGD 3c5d5067 PUD 0
Oops: 0000 [#1] SMP
...
Call Trace:
[<ffffffffa0a5bfb7>] init_vqs+0x107/0x490 [virtio_net]
[<ffffffffa0a5c9f2>] virtnet_probe+0x562/0x791815639d880be [virtio_net]
[<ffffffff8139e667>] virtio_dev_probe+0x137/0x200
[<ffffffff814c7f2a>] driver_probe_device+0x7a/0x250
[<ffffffff814c81d3>] __driver_attach+0x93/0xa0
[<ffffffff814c8140>] ? __device_attach+0x40/0x40
[<ffffffff814c6053>] bus_for_each_dev+0x63/0xa0
[<ffffffff814c7a79>] driver_attach+0x19/0x20
[<ffffffff814c76f0>] bus_add_driver+0x170/0x220
[<ffffffffa0a60000>] ? 0xffffffffa0a60000
[<ffffffff814c894f>] driver_register+0x5f/0xf0
[<ffffffff8139e41b>] register_virtio_driver+0x1b/0x30
[<ffffffffa0a60010>] virtio_net_driver_init+0x10/0x12 [virtio_net]

This patch fixes this by doing this in virtnet_free_queues(). And also
don't delete napi in virtnet_freeze() since it will call
virtnet_free_queues() which has already did this.

Fixes 9181563 ("virtio-net: rx busy polling support")
Cc: Rusty Russell <[email protected]>
Cc: Michael S. Tsirkin <[email protected]>
Signed-off-by: Jason Wang <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>
Reviewed-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
A number of tx queue wake-up events went missing due to the
outlined scenario below. Start state is a pool of 16 tx URBs,
active tx_urbs count = 15, with the netdev tx queue open.

CPU #1 [softirq]                         CPU #2 [softirq]
start_xmit()                             tx_acknowledge()
................                         ................

atomic_inc(&tx_urbs);
if (atomic_read(&tx_urbs) >= 16) {
                        -->
                                         atomic_dec(&tx_urbs);
                                         netif_wake_queue();
                                         return;
                        <--
    netif_stop_queue();
}

At the end, the correct state expected is a 15 tx_urbs count
value with the tx queue state _open_. Due to the race, we get
the same tx_urbs value but with the tx queue state _stopped_.
The wake-up event is completely lost.

Thus avoid hand-rolled concurrency mechanisms and use a proper
lock for contexts and tx queue protection.

Signed-off-by: Ahmed S. Darwish <[email protected]>
Cc: linux-stable <[email protected]>
Signed-off-by: Marc Kleine-Budde <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
The commit "drm/exynos: remove exynos_plane_dpms" (d9ea625) removed the
use of the enabled flag, which means that the code may attempt to call
win_enable on a NULL crtc. This results in the following oops on
Arndale:

[    1.673479] Unable to handle kernel NULL pointer dereference at virtual address 00000368
[    1.681500] pgd = c0004000
[    1.684154] [00000368] *pgd=00000000
[    1.687713] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[    1.693012] Modules linked in:
[    1.696045] CPU: 1 PID: 1 Comm: swapper/0 Not tainted
3.19.0-07545-g57485fa raspberrypi#1907
[    1.703524] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
(....)
[    2.014803] [<c02f9cfc>] (exynos_plane_destroy) from [<c02e61b4>] (drm_mode_config_cleanup+0x168/0x20c)
[    2.024178] [<c02e61b4>] (drm_mode_config_cleanup) from [<c02f66fc>] (exynos_drm_load+0xac/0x12c)

This patch adds in a check to ensure exynos_crtc is not NULL before it
is dereferenced.

Signed-off-by: Charles Keepax <[email protected]>
Signed-off-by: Inki Dae <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Since commit 0f04cf8 ("drm/exynos:
fix wrong pipe calculation for crtc"), fimd_clear_channel() can be
called when is_drm_iommu_supported() returns true. In this case,
the kernel is going to be panicked because crtc is not set yet.

[    1.211156] [drm] Initialized drm 1.1.0 20060810
[    1.216785] Unable to handle kernel NULL pointer dereference at virtual address 00000350
[    1.223415] pgd = c0004000
[    1.226086] [00000350] *pgd=00000000
[    1.229649] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[    1.234940] Modules linked in:
[    1.237982] CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc1-00062-g7a7cc79-dirty #123
[    1.246136] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    1.252214] task: ee8c8000 ti: ee8d0000 task.ti: ee8d0000
[    1.257606] PC is at fimd_wait_for_vblank+0x8/0xc8
[    1.262370] LR is at fimd_bind+0x138/0x1a8
[    1.266450] pc : [<c02fb63c>]    lr : [<c02fb834>]    psr: 20000113
[    1.266450] sp : ee8d1d28  ip : 00000000  fp : 00000000
[    1.277906] r10: 00000001  r9 : c09d693c  r8 : c0a2d6a8
[    1.283114] r7 : 00000034  r6 : 00000001  r5 : ee0bb400  r4 : ee244c10
[    1.289624] r3 : 00000000  r2 : 00000000  r1 : 00000001  r0 : 00000000
[    1.296135] Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[    1.303426] Control: 10c5387d  Table: 4000404a  DAC: 00000015
[    1.309154] Process swapper/0 (pid: 1, stack limit = 0xee8d0210)
[    1.315143] Stack: (0xee8d1d28 to 0xee8d2000)
[    1.319486] 1d20:                   00000000 c0113d18 ee0bb400 ee0bb400 ee245c30 eebbe210
[    1.327645] 1d40: ee008a40 ee244c10 ee0bb400 00000001 00000034 c02fb834 00000000 c030a858
[    1.335804] 1d60: ee244a10 eeb60780 ee008a40 eeb60740 ee0bb400 c03030d0 00000000 00000000
[    1.343963] 1d80: ee244a10 ee0bb400 00000000 eeb60740 eeb60810 00000000 00000000 c02f6ba4
[    1.352123] 1da0: ee0bb400 00000000 00000000 c02e0500 ee244a00 c0a04a14 ee0bb400 c02e1de4
[    1.360282] 1dc0: 00000000 c030a858 00000002 eeb60820 eeb60820 00000002 eeb60780 c03033d4
[    1.368441] 1de0: c06e9cec 00000000 ee244a10 eeb60780 c0a056f8 c03035fc c0a04b24 c0a04b24
[    1.376600] 1e00: ee244a10 00000001 c0a049d0 c02f6d34 c0ad462c eeba0790 00000000 ee244a10
[    1.384759] 1e20: ffffffed c0a049d0 00000000 c03090b0 ee244a10 c0ad462c c0a2d840 c03077a0
[    1.392919] 1e40: eeb5e880 c024b738 000008db ee244a10 c0a049d0 ee244a44 00000000 c09e71d8
[    1.401078] 1e60: 000000c6 c0307a6c c0a049d0 00000000 c03079e0 c0305ea8 ee826e5c ee1dc7b4
[    1.409237] 1e80: c0a049d0 eeb5e880 c0a058a8 c0306e2c c0896204 c0a049d0 c06e9d10 c0a049d0
[    1.417396] 1ea0: c06e9d10 c0ad4600 00000000 c0308360 00000000 00000003 c06e9d10 c02f6e14
[    1.425555] 1ec0: 00000000 c0896204 ffffffff 00000000 00000000 00000000 00000000 00000000
[    1.433714] 1ee0: 00000000 00000000 c02f6d5c c02f6d5c 00000000 eeb5d740 c09e71d8 c0008a30
[    1.441874] 1f00: ef7fca5e 00000000 00000000 00000066 00000000 ee8d1f28 c003ff1c c02514e8
[    1.450033] 1f20: 60000113 ffffffff c093906c ef7fca5e 000000c6 c004018c 00000000 c093906c
[    1.458192] 1f40: c08a9690 c093840c 00000006 00000006 c09eb2ac c09c0d74 00000006 c09c0d54
[    1.466351] 1f60: c0a3d680 c09745a0 c09d693c 000000c6 00000000 c0974db4 00000006 00000006
[    1.474510] 1f80: c09745a0 ffffffff 00000000 c0692e00 00000000 00000000 00000000 00000000
[    1.482669] 1fa0: 00000000 c0692e08 00000000 c000f040 00000000 00000000 00000000 00000000
[    1.490828] 1fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    1.498988] 1fe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
[    1.507159] [<c02fb63c>] (fimd_wait_for_vblank) from [<c02fb834>] (fimd_bind+0x138/0x1a8)
[    1.515313] [<c02fb834>] (fimd_bind) from [<c03030d0>] (component_bind_all+0xc4/0x20c)
[    1.523209] [<c03030d0>] (component_bind_all) from [<c02f6ba4>] (exynos_drm_load+0xa0/0x140)
[    1.531632] [<c02f6ba4>] (exynos_drm_load) from [<c02e0500>] (drm_dev_register+0xa0/0xf4)
[    1.539788] [<c02e0500>] (drm_dev_register) from [<c02e1de4>] (drm_platform_init+0x44/0xcc)
[    1.548121] [<c02e1de4>] (drm_platform_init) from [<c03033d4>] (try_to_bring_up_master.part.1+0xc8/0x104)
[    1.557668] [<c03033d4>] (try_to_bring_up_master.part.1) from [<c03035fc>] (component_master_add_with_match+0xd0/0x118)
[    1.568431] [<c03035fc>] (component_master_add_with_match) from [<c02f6d34>] (exynos_drm_platform_probe+0xf0/0x118)
[    1.578847] [<c02f6d34>] (exynos_drm_platform_probe) from [<c03090b0>] (platform_drv_probe+0x48/0x98)
[    1.588052] [<c03090b0>] (platform_drv_probe) from [<c03077a0>] (driver_probe_device+0x140/0x380)
[    1.596902] [<c03077a0>] (driver_probe_device) from [<c0307a6c>] (__driver_attach+0x8c/0x90)
[    1.605321] [<c0307a6c>] (__driver_attach) from [<c0305ea8>] (bus_for_each_dev+0x54/0x88)
[    1.613480] [<c0305ea8>] (bus_for_each_dev) from [<c0306e2c>] (bus_add_driver+0xec/0x200)
[    1.621640] [<c0306e2c>] (bus_add_driver) from [<c0308360>] (driver_register+0x78/0xf4)
[    1.629625] [<c0308360>] (driver_register) from [<c02f6e14>] (exynos_drm_init+0xb8/0x11c)
[    1.637785] [<c02f6e14>] (exynos_drm_init) from [<c0008a30>] (do_one_initcall+0xac/0x1ec)
[    1.645950] [<c0008a30>] (do_one_initcall) from [<c0974db4>] (kernel_init_freeable+0x194/0x268)
[    1.654626] [<c0974db4>] (kernel_init_freeable) from [<c0692e08>] (kernel_init+0x8/0xe4)
[    1.662699] [<c0692e08>] (kernel_init) from [<c000f040>] (ret_from_fork+0x14/0x34)
[    1.670246] Code: eaffffd5 c09df884 e92d40f0 e24dd01c (e5905350)
[    1.676408] ---[ end trace 804468492f306a6f ]---
[    1.680948] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[    1.680948]
[    1.690035] CPU1: stopping
[    1.692727] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G      D         4.0.0-rc1-00062-g7a7cc79-dirty #123
[    1.702097] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    1.708192] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14)
[    1.715908] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8)
[    1.723108] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4)
[    1.730485] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c)
[    1.738036] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74)
[    1.745498] Exception stack(0xee8fdf98 to 0xee8fdfe0)
[    1.750533] df80:                                                       00000000 00000000
[    1.758695] dfa0: ee8fdfe8 c0021780 c09df938 00000015 10c0387d c0a3d988 4000406a c09df8d4
[    1.766853] dfc0: c0a27a74 c09df94 01000000 ee8fdfe0 c00101c0 c00101c4 60000113 ffffffff
[    1.775015] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c)
[    1.782397] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324)
[    1.790639] [<c005e804>] (cpu_startup_entry) from [<40008764>] (0x40008764)
[    1.797579] CPU0: stopping
[    1.800272] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G      D         4.0.0-rc1-00062-g7a7cc79-dirty #123
[    1.809642] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    1.815730] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14)
[    1.823450] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8)
[    1.830653] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4)
[    1.838030] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c)
[    1.845581] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74)
[    1.853043] Exception stack(0xc09ddf60 to 0xc09ddfa8)
[    1.858081] df60: 00000000 00000000 c09ddfb0 c0021780 c09df938 00000001 ffffffff c0a3d680
[    1.866239] df80: c09c0dec c09df8d4 c0a27a74 c09df94 01000000 c09ddfa8 c00101c0 c00101c4
[    1.874396] dfa0: 60000113 ffffffff
[    1.877872] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c)
[    1.885251] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324)
[    1.893499] [<c005e804>] (cpu_startup_entry) from [<c0974bc8>] (start_kernel+0x324/0x37c)
[    1.901655] [<c0974bc8>] (start_kernel) from [<40008074>] (0x40008074)
[    1.908161] CPU3: stopping
[    1.910855] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G      D         4.0.0-rc1-00062-g7a7cc79-dirty #123
[    1.920225] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    1.926313] [<c0016c84>] (unwind_backtrace) from [<c00129bc>] (show_stack+0x10/0x14)
[    1.934034] [<c00129bc>] (show_stack) from [<c0696f58>] (dump_stack+0x78/0xc8)
[    1.941237] [<c0696f58>] (dump_stack) from [<c0015020>] (handle_IPI+0x16c/0x2b4)
[    1.948613] [<c0015020>] (handle_IPI) from [<c00086bc>] (gic_handle_irq+0x64/0x6c)
[    1.956165] [<c00086bc>] (gic_handle_irq) from [<c00134c0>] (__irq_svc+0x40/0x74)
[    1.963626] Exception stack(0xee901f98 to 0xee901fe0)
[    1.968661] 1f80:                                                       00000000 00000000
[    1.976823] 1fa0: ee901fe8 c0021780 c09df938 00000015 10c0387d c0a3d988 4000406a c09df8d4
[    1.984982] 1fc0: c0a27a74 c09df94 01000000 ee901fe0 c00101c0 c00101c4 60000113 ffffffff
[    1.993143] [<c00134c0>] (__irq_svc) from [<c00101c4>] (arch_cpu_idle+0x30/0x3c)
[    2.000522] [<c00101c4>] (arch_cpu_idle) from [<c005e804>] (cpu_startup_entry+0x180/0x324)
[    2.008765] [<c005e804>] (cpu_startup_entry) from [<40008764>] (0x40008764)
[    2.015710] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b

Signed-off-by: Hyungwon Hwang <[email protected]>
Signed-off-by: Inki Dae <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
SAS controller has its own tag allocation, which doesn't directly match to ATA
tag, so SAS and SATA have different code path for ata tags. Originally we use
port->scsi_host (98bd4be) to destinguish SAS controller, but libsas set
->scsi_host too, so we can't use it for the destinguish, we add a new flag for
this purpose.

Without this patch, the following oops can happen because scsi-mq uses
a host-wide tag map shared among all devices with some integer tag
values >= ATA_MAX_QUEUE.  These unexpectedly high tag values cause
__ata_qc_from_tag() to return NULL, which is then dereferenced in
ata_qc_new_init().

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
  IP: [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
  PGD 32adf0067 PUD 32adf1067 PMD 0
  Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
  Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi igb
  i2c_algo_bit ptp pps_core pm80xx libsas scsi_transport_sas sg coretemp
  eeprom w83795 i2c_i801
  CPU: 4 PID: 1450 Comm: cydiskbench Not tainted 4.0.0-rc3 #1
  Hardware name: Supermicro X8DTH-i/6/iF/6F/X8DTH, BIOS 2.1b       05/04/12
  task: ffff8800ba86d500 ti: ffff88032a064000 task.ti: ffff88032a064000
  RIP: 0010:[<ffffffff804fd46e>]  [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
  RSP: 0018:ffff88032a067858  EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffff8800ba0d2230 RCX: 000000000000002a
  RDX: ffffffff80505ae0 RSI: 0000000000000020 RDI: ffff8800ba0d2230
  RBP: ffff88032a067868 R08: 0000000000000201 R09: 0000000000000001
  R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800ba0d0000
  R13: ffff8800ba0d2230 R14: ffffffff80505ae0 R15: ffff8800ba0d0000
  FS:  0000000041223950(0063) GS:ffff88033e480000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000058 CR3: 000000032a0a3000 CR4: 00000000000006e0
  Stack:
   ffff880329eee758 ffff880329eee758 ffff88032a0678a8 ffffffff80502dad
   ffff8800ba167978 ffff880329eee758 ffff88032bf9c520 ffff8800ba167978
   ffff88032bf9c520 ffff88032bf9a290 ffff88032a0678b8 ffffffff80506909
  Call Trace:
   [<ffffffff80502dad>] ata_scsi_translate+0x3d/0x1b0
   [<ffffffff80506909>] ata_sas_queuecmd+0x149/0x2a0
   [<ffffffffa0046650>] sas_queuecommand+0xa0/0x1f0 [libsas]
   [<ffffffff804ea544>] scsi_dispatch_cmd+0xd4/0x1a0
   [<ffffffff804eb50f>] scsi_queue_rq+0x66f/0x7f0
   [<ffffffff803e5098>] __blk_mq_run_hw_queue+0x208/0x3f0
   [<ffffffff803e54b8>] blk_mq_run_hw_queue+0x88/0xc0
   [<ffffffff803e5c74>] blk_mq_insert_request+0xc4/0x130
   [<ffffffff803e0b63>] blk_execute_rq_nowait+0x73/0x160
   [<ffffffffa0023fca>] sg_common_write+0x3da/0x720 [sg]
   [<ffffffffa0025100>] sg_new_write+0x250/0x360 [sg]
   [<ffffffffa0025feb>] sg_write+0x13b/0x450 [sg]
   [<ffffffff8032ec91>] vfs_write+0xd1/0x1b0
   [<ffffffff8032ee54>] SyS_write+0x54/0xc0
   [<ffffffff80689932>] system_call_fastpath+0x12/0x17

tj: updated description.

Fixes: 12cb5ce ("libata: use blk taging")
Reported-and-tested-by: Tony Battersby <[email protected]>
Signed-off-by: Shaohua Li <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
This patch fixes a NULL pointer dereference when enabling regmap event
tracing in the presence of a syscon regmap, introduced by commit bdb0066
("mfd: syscon: Decouple syscon interface from platform devices").
That patch introduced syscon regmaps that have their dev field set to NULL.
The regmap trace events expect it to point to a valid struct device and feed
it to dev_name():

  $ echo 1 > /sys/kernel/debug/tracing/events/regmap/enable

  Unable to handle kernel NULL pointer dereference at virtual address 0000002c
  pgd = 80004000
  [0000002c] *pgd=00000000
  Internal error: Oops: 17 [#1] SMP ARM
  Modules linked in: coda videobuf2_vmalloc
  CPU: 0 PID: 304 Comm: kworker/0:2 Not tainted 4.0.0-rc2+ #9197
  Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
  Workqueue: events_freezable thermal_zone_device_check
  task: 9f25a200 ti: 9f1ee000 task.ti: 9f1ee000
  PC is at ftrace_raw_event_regmap_block+0x3c/0xe4
  LR is at _regmap_raw_read+0x1bc/0x1cc
  pc : [<803636e8>]    lr : [<80365f2c>]    psr: 600f0093
  sp : 9f1efd78  ip : 9f1efdb8  fp : 9f1efdb4
  r10: 00000004  r9 : 00000001  r8 : 00000001
  r7 : 00000180  r6 : 00000000  r5 : 9f00e3c0  r4 : 00000003
  r3 : 00000001  r2 : 00000180  r1 : 00000000  r0 : 9f00e3c0
  Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
  Control: 10c5387d  Table: 2d91004a  DAC: 00000015
  Process kworker/0:2 (pid: 304, stack limit = 0x9f1ee210)
  Stack: (0x9f1efd78 to 0x9f1f0000)
  fd60:                                                       9f1efda4 9f1efd88
  fd80: 800708c0 805f9510 80927140 800f0013 9f1fc800 9eb2f490 00000000 00000180
  fda0: 808e3840 00000001 9f1efdfc 9f1efdb8 80365f2c 803636b8 805f8958 800708e0
  fdc0: a00f0013 803636ac 9f16de00 00000180 80927140 9f1fc800 9f1fc800 9f1efe6c
  fde0: 9f1efe6c 9f732400 00000000 00000000 9f1efe1c 9f1efe00 80365f70 80365d7c
  fe00: 80365f3c 9f1fc800 9f1fc800 00000180 9f1efe44 9f1efe20 803656a4 80365f48
  fe20: 9f1fc800 00000180 9f1efe6c 9f1efe6c 9f732400 00000000 9f1efe64 9f1efe48
  fe40: 803657bc 80365634 00000001 9e95f910 9f1fc800 9f1efeb4 9f1efe8c 9f1efe68
  fe60: 80452ac0 80365778 9f1efe8c 9f1efe78 9e93d400 9e93d5e8 9f1efeb4 9f72ef40
  fe80: 9f1efeac 9f1efe90 8044e11c 80452998 8045298c 9e93d608 9e93d400 808e1978
  fea0: 9f1efecc 9f1efeb0 8044fd14 8044e0d0 ffffffff 9f25a200 9e93d608 9e481380
  fec0: 9f1efedc 9f1efed0 8044fde8 8044fcec 9f1eff1c 9f1efee0 80038d50 8044fdd8
  fee0: 9f1ee020 9f72ef40 9e481398 00000000 00000008 9f72ef54 9f1ee020 9f72ef40
  ff00: 9e481398 9e481380 00000008 9f72ef40 9f1eff5c 9f1eff20 80039754 80038bfc
  ff20: 00000000 9e481380 80894100 808e1662 00000000 9e4f2ec0 00000000 9e481380
  ff40: 800396f8 00000000 00000000 00000000 9f1effac 9f1eff60 8003e020 80039704
  ff60: ffffffff 00000000 ffffffff 9e481380 00000000 00000000 9f1eff78 9f1eff78
  ff80: 00000000 00000000 9f1eff88 9f1eff88 9e4f2ec0 8003df30 00000000 00000000
  ffa0: 00000000 9f1effb0 8000eb60 8003df3c 00000000 00000000 00000000 00000000
  ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
  ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
  Backtrace:
  [<803636ac>] (ftrace_raw_event_regmap_block) from [<80365f2c>] (_regmap_raw_read+0x1bc/0x1cc)
   r9:00000001 r8:808e3840 r7:00000180 r6:00000000 r5:9eb2f490 r4:9f1fc800
  [<80365d70>] (_regmap_raw_read) from [<80365f70>] (_regmap_bus_read+0x34/0x6c)
   r10:00000000 r9:00000000 r8:9f732400 r7:9f1efe6c r6:9f1efe6c r5:9f1fc800
   r4:9f1fc800
  [<80365f3c>] (_regmap_bus_read) from [<803656a4>] (_regmap_read+0x7c/0x144)
   r6:00000180 r5:9f1fc800 r4:9f1fc800 r3:80365f3c
  [<80365628>] (_regmap_read) from [<803657bc>] (regmap_read+0x50/0x70)
   r9:00000000 r8:9f732400 r7:9f1efe6c r6:9f1efe6c r5:00000180 r4:9f1fc800
  [<8036576c>] (regmap_read) from [<80452ac0>] (imx_get_temp+0x134/0x1a4)
   r6:9f1efeb4 r5:9f1fc800 r4:9e95f910 r3:00000001
  [<8045298c>] (imx_get_temp) from [<8044e11c>] (thermal_zone_get_temp+0x58/0x74)
   r7:9f72ef40 r6:9f1efeb4 r5:9e93d5e8 r4:9e93d400
  [<8044e0c4>] (thermal_zone_get_temp) from [<8044fd14>] (thermal_zone_device_update+0x34/0xec)
   r6:808e1978 r5:9e93d400 r4:9e93d608 r3:8045298c
  [<8044fce0>] (thermal_zone_device_update) from [<8044fde8>] (thermal_zone_device_check+0x1c/0x20)
   r5:9e481380 r4:9e93d608
  [<8044fdcc>] (thermal_zone_device_check) from [<80038d50>] (process_one_work+0x160/0x3d4)
  [<80038bf0>] (process_one_work) from [<80039754>] (worker_thread+0x5c/0x4f4)
   r10:9f72ef40 r9:00000008 r8:9e481380 r7:9e481398 r6:9f72ef40 r5:9f1ee020
   r4:9f72ef54
  [<800396f8>] (worker_thread) from [<8003e020>] (kthread+0xf0/0x108)
   r10:00000000 r9:00000000 r8:00000000 r7:800396f8 r6:9e481380 r5:00000000
   r4:9e4f2ec0
  [<8003df30>] (kthread) from [<8000eb60>] (ret_from_fork+0x14/0x34)
   r7:00000000 r6:00000000 r5:8003df30 r4:9e4f2ec0
  Code: e3140040 1a00001a e3140020 1a000016 (e596002c)
  ---[ end trace 193c15c2494ec960 ]---

Fixes: bdb0066 (mfd: syscon: Decouple syscon interface from platform devices)
Signed-off-by: Philipp Zabel <[email protected]>
Signed-off-by: Mark Brown <[email protected]>
Cc: [email protected]
anholt pushed a commit that referenced this pull request Apr 21, 2015
…lpcr()

Currently, kvmppc_set_lpcr() has a spinlock around the whole function,
and inside that does mutex_lock(&kvm->lock).  It is not permitted to
take a mutex while holding a spinlock, because the mutex_lock might
call schedule().  In addition, this causes lockdep to warn about a
lock ordering issue:

======================================================
[ INFO: possible circular locking dependency detected ]
3.18.0-kvm-04645-gdfea862-dirty #131 Not tainted
-------------------------------------------------------
qemu-system-ppc/8179 is trying to acquire lock:
 (&kvm->lock){+.+.+.}, at: [<d00000000ecc1f54>] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]

but task is already holding lock:
 (&(&vcore->lock)->rlock){+.+...}, at: [<d00000000ecc1ea0>] .kvmppc_set_lpcr+0x40/0x1c0 [kvm_hv]

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #1 (&(&vcore->lock)->rlock){+.+...}:
       [<c000000000b3c120>] .mutex_lock_nested+0x80/0x570
       [<d00000000ecc7a14>] .kvmppc_vcpu_run_hv+0xc4/0xe40 [kvm_hv]
       [<d00000000eb9f5cc>] .kvmppc_vcpu_run+0x2c/0x40 [kvm]
       [<d00000000eb9cb24>] .kvm_arch_vcpu_ioctl_run+0x54/0x160 [kvm]
       [<d00000000eb94478>] .kvm_vcpu_ioctl+0x4a8/0x7b0 [kvm]
       [<c00000000026cbb4>] .do_vfs_ioctl+0x444/0x770
       [<c00000000026cfa4>] .SyS_ioctl+0xc4/0xe0
       [<c000000000009264>] syscall_exit+0x0/0x98

-> #0 (&kvm->lock){+.+.+.}:
       [<c0000000000ff28c>] .lock_acquire+0xcc/0x1a0
       [<c000000000b3c120>] .mutex_lock_nested+0x80/0x570
       [<d00000000ecc1f54>] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]
       [<d00000000ecc510c>] .kvmppc_set_one_reg_hv+0x4dc/0x990 [kvm_hv]
       [<d00000000eb9f234>] .kvmppc_set_one_reg+0x44/0x330 [kvm]
       [<d00000000eb9c9dc>] .kvm_vcpu_ioctl_set_one_reg+0x5c/0x150 [kvm]
       [<d00000000eb9ced4>] .kvm_arch_vcpu_ioctl+0x214/0x2c0 [kvm]
       [<d00000000eb940b0>] .kvm_vcpu_ioctl+0xe0/0x7b0 [kvm]
       [<c00000000026cbb4>] .do_vfs_ioctl+0x444/0x770
       [<c00000000026cfa4>] .SyS_ioctl+0xc4/0xe0
       [<c000000000009264>] syscall_exit+0x0/0x98

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&(&vcore->lock)->rlock);
                               lock(&kvm->lock);
                               lock(&(&vcore->lock)->rlock);
  lock(&kvm->lock);

 *** DEADLOCK ***

2 locks held by qemu-system-ppc/8179:
 #0:  (&vcpu->mutex){+.+.+.}, at: [<d00000000eb93f18>] .vcpu_load+0x28/0x90 [kvm]
 #1:  (&(&vcore->lock)->rlock){+.+...}, at: [<d00000000ecc1ea0>] .kvmppc_set_lpcr+0x40/0x1c0 [kvm_hv]

stack backtrace:
CPU: 4 PID: 8179 Comm: qemu-system-ppc Not tainted 3.18.0-kvm-04645-gdfea862-dirty #131
Call Trace:
[c000001a66c0f310] [c000000000b486ac] .dump_stack+0x88/0xb4 (unreliable)
[c000001a66c0f390] [c0000000000f8bec] .print_circular_bug+0x27c/0x3d0
[c000001a66c0f440] [c0000000000fe9e8] .__lock_acquire+0x2028/0x2190
[c000001a66c0f5d0] [c0000000000ff28c] .lock_acquire+0xcc/0x1a0
[c000001a66c0f6a0] [c000000000b3c120] .mutex_lock_nested+0x80/0x570
[c000001a66c0f7c0] [d00000000ecc1f54] .kvmppc_set_lpcr+0xf4/0x1c0 [kvm_hv]
[c000001a66c0f860] [d00000000ecc510c] .kvmppc_set_one_reg_hv+0x4dc/0x990 [kvm_hv]
[c000001a66c0f8d0] [d00000000eb9f234] .kvmppc_set_one_reg+0x44/0x330 [kvm]
[c000001a66c0f960] [d00000000eb9c9dc] .kvm_vcpu_ioctl_set_one_reg+0x5c/0x150 [kvm]
[c000001a66c0f9f0] [d00000000eb9ced4] .kvm_arch_vcpu_ioctl+0x214/0x2c0 [kvm]
[c000001a66c0faf0] [d00000000eb940b0] .kvm_vcpu_ioctl+0xe0/0x7b0 [kvm]
[c000001a66c0fcb0] [c00000000026cbb4] .do_vfs_ioctl+0x444/0x770
[c000001a66c0fd90] [c00000000026cfa4] .SyS_ioctl+0xc4/0xe0
[c000001a66c0fe30] [c000000000009264] syscall_exit+0x0/0x98

This fixes it by moving the mutex_lock()/mutex_unlock() pair outside
the spin-locked region.

Signed-off-by: Paul Mackerras <[email protected]>
Signed-off-by: Alexander Graf <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
If register_shrinker() failed, nfsd will cause a NULL pointer access as,

[ 9250.875465] nfsd: last server has exited, flushing export cache
[ 9251.427270] BUG: unable to handle kernel NULL pointer dereference at           (null)
[ 9251.427393] IP: [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.427579] PGD 13e4d067 PUD 13e4c067 PMD 0
[ 9251.427633] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
[ 9251.427706] Modules linked in: ip6t_rpfilter ip6t_REJECT bnep bluetooth xt_conntrack cfg80211 rfkill ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw ip6table_filter ip6_tables iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_security iptable_raw btrfs xfs microcode ppdev serio_raw pcspkr xor libcrc32c raid6_pq e1000 parport_pc parport i2c_piix4 i2c_core nfsd(OE-) auth_rpcgss nfs_acl lockd sunrpc(E) ata_generic pata_acpi
[ 9251.428240] CPU: 0 PID: 1557 Comm: rmmod Tainted: G           OE 3.16.0-rc2+ #22
[ 9251.428366] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013
[ 9251.428496] task: ffff880000849540 ti: ffff8800136f4000 task.ti: ffff8800136f4000
[ 9251.428593] RIP: 0010:[<ffffffff8136fc29>]  [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.428696] RSP: 0018:ffff8800136f7ea0  EFLAGS: 00010207
[ 9251.428751] RAX: 0000000000000000 RBX: ffffffffa0116d48 RCX: dead000000200200
[ 9251.428814] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa0116d48
[ 9251.428876] RBP: ffff8800136f7ea0 R08: ffff8800136f4000 R09: 0000000000000001
[ 9251.428939] R10: 8080808080808080 R11: 0000000000000000 R12: ffffffffa011a5a0
[ 9251.429002] R13: 0000000000000800 R14: 0000000000000000 R15: 00000000018ac090
[ 9251.429064] FS:  00007fb9acef0740(0000) GS:ffff88003fa00000(0000) knlGS:0000000000000000
[ 9251.429164] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 9251.429221] CR2: 0000000000000000 CR3: 0000000031a17000 CR4: 00000000001407f0
[ 9251.429306] Stack:
[ 9251.429410]  ffff8800136f7eb8 ffffffff8136fcdd ffffffffa0116d20 ffff8800136f7ed0
[ 9251.429511]  ffffffff8118a0f2 0000000000000000 ffff8800136f7ee0 ffffffffa00eb765
[ 9251.429610]  ffff8800136f7ef0 ffffffffa010e93c ffff8800136f7f78 ffffffff81104ac2
[ 9251.429709] Call Trace:
[ 9251.429755]  [<ffffffff8136fcdd>] list_del+0xd/0x30
[ 9251.429896]  [<ffffffff8118a0f2>] unregister_shrinker+0x22/0x40
[ 9251.430037]  [<ffffffffa00eb765>] nfsd_reply_cache_shutdown+0x15/0x90 [nfsd]
[ 9251.430106]  [<ffffffffa010e93c>] exit_nfsd+0x9/0x6cd [nfsd]
[ 9251.430192]  [<ffffffff81104ac2>] SyS_delete_module+0x162/0x200
[ 9251.430280]  [<ffffffff81013b69>] ? do_notify_resume+0x59/0x90
[ 9251.430395]  [<ffffffff816f2369>] system_call_fastpath+0x16/0x1b
[ 9251.430457] Code: 00 00 55 48 8b 17 48 b9 00 01 10 00 00 00 ad de 48 8b 47 08 48 89 e5 48 39 ca 74 29 48 b9 00 02 20 00 00 00 ad de 48 39 c8 74 7a <4c> 8b 00 4c 39 c7 75 53 4c 8b 42 08 4c 39 c7 75 2b 48 89 42 08
[ 9251.430691] RIP  [<ffffffff8136fc29>] __list_del_entry+0x29/0xd0
[ 9251.430755]  RSP <ffff8800136f7ea0>
[ 9251.430805] CR2: 0000000000000000
[ 9251.431033] ---[ end trace 080f3050d082b4ea ]---

Signed-off-by: Kinglong Mee <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
We occasionally see in procedure mlx4_GEN_EQE that the driver tries
to grab an uninitialized mutex.

This can occur in only one of two ways:
1. We are trying to generate an async event on an uninitialized slave.
2. We are trying to generate an async event on an illegal slave number
   ( < 0 or > persist->num_vfs) or an inactive slave.

To deal with #1: move the mutex initialization from specific slave init
sequence in procedure mlx_master_do_cmd to mlx4_multi_func_init() (so that
the mutex is always initialized for all slaves).

To deal with #2: check in procedure mlx4_GEN_EQE that the slave number
provided is in the proper range and that the slave is active.

Signed-off-by: Jack Morgenstein <[email protected]>
Signed-off-by: Or Gerlitz <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Qiu Xishi reported the following BUG when testing hot-add/hot-remove node under
stress condition:

  BUG: unable to handle kernel paging request at 0000000000025f60
  IP: next_online_pgdat+0x1/0x50
  PGD 0
  Oops: 0000 [#1] SMP
  ACPI: Device does not support D3cold
  Modules linked in: fuse nls_iso8859_1 nls_cp437 vfat fat loop dm_mod coretemp mperf crc32c_intel ghash_clmulni_intel aesni_intel ablk_helper cryptd lrw gf128mul glue_helper aes_x86_64 pcspkr microcode igb dca i2c_algo_bit ipv6 megaraid_sas iTCO_wdt i2c_i801 i2c_core iTCO_vendor_support tg3 sg hwmon ptp lpc_ich pps_core mfd_core acpi_pad rtc_cmos button ext3 jbd mbcache sd_mod crc_t10dif scsi_dh_alua scsi_dh_rdac scsi_dh_hp_sw scsi_dh_emc scsi_dh ahci libahci libata scsi_mod [last unloaded: rasf]
  CPU: 23 PID: 238 Comm: kworker/23:1 Tainted: G           O 3.10.15-5885-euler0302 #1
  Hardware name: HUAWEI TECHNOLOGIES CO.,LTD. Huawei N1/Huawei N1, BIOS V100R001 03/02/2015
  Workqueue: events vmstat_update
  task: ffffa800d32c0000 ti: ffffa800d32ae000 task.ti: ffffa800d32ae000
  RIP: 0010: next_online_pgdat+0x1/0x50
  RSP: 0018:ffffa800d32afce8  EFLAGS: 00010286
  RAX: 0000000000001440 RBX: ffffffff81da53b8 RCX: 0000000000000082
  RDX: 0000000000000000 RSI: 0000000000000082 RDI: 0000000000000000
  RBP: ffffa800d32afd28 R08: ffffffff81c93bfc R09: ffffffff81cbdc96
  R10: 00000000000040ec R11: 00000000000000a0 R12: ffffa800fffb3440
  R13: ffffa800d32afd38 R14: 0000000000000017 R15: ffffa800e6616800
  FS:  0000000000000000(0000) GS:ffffa800e6600000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000025f60 CR3: 0000000001a0b000 CR4: 00000000001407e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
    refresh_cpu_vm_stats+0xd0/0x140
    vmstat_update+0x11/0x50
    process_one_work+0x194/0x3d0
    worker_thread+0x12b/0x410
    kthread+0xc6/0xd0
    ret_from_fork+0x7c/0xb0

The cause is the "memset(pgdat, 0, sizeof(*pgdat))" at the end of
try_offline_node, which will reset all the content of pgdat to 0, as the
pgdat is accessed lock-free, so that the users still using the pgdat
will panic, such as the vmstat_update routine.

process A:				offline node XX:

vmstat_updat()
   refresh_cpu_vm_stats()
     for_each_populated_zone()
       find online node XX
     cond_resched()
					offline cpu and memory, then try_offline_node()
					node_set_offline(nid), and memset(pgdat, 0, sizeof(*pgdat))
       zone = next_zone(zone)
         pg_data_t *pgdat = zone->zone_pgdat;  // here pgdat is NULL now
           next_online_pgdat(pgdat)
             next_online_node(pgdat->node_id);  // NULL pointer access

So the solution here is postponing the reset of obsolete pgdat from
try_offline_node() to hotadd_new_pgdat(), and just resetting
pgdat->nr_zones and pgdat->classzone_idx to be 0 rather than the memset
0 to avoid breaking pointer information in pgdat.

Signed-off-by: Gu Zheng <[email protected]>
Reported-by: Xishi Qiu <[email protected]>
Suggested-by: KAMEZAWA Hiroyuki <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Taku Izumi <[email protected]>
Cc: Tang Chen <[email protected]>
Cc: Xie XiuQi <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
anholt pushed a commit that referenced this pull request Apr 21, 2015
Commit 3c60509 ("mm/page_alloc: restrict max order of merging on
isolated pageblock") changed the logic of unset_migratetype_isolate to
check the buddy allocator and explicitly call __free_pages to merge.

The page that is being freed in this path never had prep_new_page called
so set_page_refcounted is called explicitly but there is no call to
kernel_map_pages.  With the default kernel_map_pages this is mostly
harmless but if kernel_map_pages does any manipulation of the page
tables (unmapping or setting pages to read only) this may trigger a
fault:

    alloc_contig_range test_pages_isolated(ceb00, ced00) failed
    Unable to handle kernel paging request at virtual address ffffffc0cec00000
    pgd = ffffffc045fc4000
    [ffffffc0cec00000] *pgd=0000000000000000
    Internal error: Oops: 9600004f [#1] PREEMPT SMP
    Modules linked in: exfatfs
    CPU: 1 PID: 23237 Comm: TimedEventQueue Not tainted 3.10.49-gc72ad36-dirty #1
    task: ffffffc03de52100 ti: ffffffc015388000 task.ti: ffffffc015388000
    PC is at memset+0xc8/0x1c0
    LR is at kernel_map_pages+0x1ec/0x244

Fix this by calling kernel_map_pages to ensure the page is set in the
page table properly

Fixes: 3c60509 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Laura Abbott <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Cc: Mel Gorman <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Yasuaki Ishimatsu <[email protected]>
Cc: Zhang Yanfei <[email protected]>
Cc: Xishi Qiu <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Acked-by: Joonsoo Kim <[email protected]>
Cc: Gioh Kim <[email protected]>
Cc: Michal Nazarewicz <[email protected]>
Cc: Marek Szyprowski <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
anholt pushed a commit that referenced this pull request Feb 20, 2019
If fbdev setup has failed, lastclose will give a NULL pointer deref:

[   77.794295] [drm:drm_lastclose]
[   77.794414] [drm:drm_lastclose] driver lastclose completed
[   77.794660] Unable to handle kernel NULL pointer dereference at virtual address 00000014
[   77.809460] pgd = b376b71b
[   77.818275] [00000014] *pgd=175ba831, *pte=00000000, *ppte=00000000
[   77.830813] Internal error: Oops: 17 [#1] ARM
[   77.840963] Modules linked in: mi0283qt mipi_dbi tinydrm raspberrypi_hwmon gpio_backlight backlight snd_bcm2835(C) bcm2835_rng rng_core
[   77.865203] CPU: 0 PID: 527 Comm: lt-modetest Tainted: G         C        5.0.0-rc1+ #1
[   77.879525] Hardware name: BCM2835
[   77.889185] PC is at restore_fbdev_mode+0x20/0x164
[   77.900261] LR is at drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0x9c
[   78.002446] Process lt-modetest (pid: 527, stack limit = 0x7a3d5c14)
[   78.291030] Backtrace:
[   78.300815] [<c04f2d0c>] (restore_fbdev_mode) from [<c04f4708>] (drm_fb_helper_restore_fbdev_mode_unlocked+0x54/0x9c)
[   78.319095]  r9:d8a8a288 r8:d891acf0 r7:d7697910 r6:00000000 r5:d891ac00 r4:d891ac00
[   78.334432] [<c04f46b4>] (drm_fb_helper_restore_fbdev_mode_unlocked) from [<c04f47e8>] (drm_fbdev_client_restore+0x18/0x20)
[   78.353296]  r8:d76978c0 r7:d7697910 r6:d7697950 r5:d7697800 r4:d891ac00 r3:c04f47d0
[   78.368689] [<c04f47d0>] (drm_fbdev_client_restore) from [<c051b6b4>] (drm_client_dev_restore+0x7c/0xc0)
[   78.385982] [<c051b638>] (drm_client_dev_restore) from [<c04f8fd0>] (drm_lastclose+0xc4/0xd4)
[   78.402332]  r8:d76978c0 r7:d7471080 r6:c0e0c088 r5:d8a85e00 r4:d7697800
[   78.416688] [<c04f8f0c>] (drm_lastclose) from [<c04f9088>] (drm_release+0xa8/0x10c)
[   78.431929]  r5:d8a85e00 r4:d7697800
[   78.442989] [<c04f8fe0>] (drm_release) from [<c02640c4>] (__fput+0x104/0x1c8)
[   78.457740]  r8:d5ccea10 r7:d96cfb10 r6:00000008 r5:d74c1b90 r4:d8a8a280
[   78.472043] [<c0263fc0>] (__fput) from [<c02641ec>] (____fput+0x18/0x1c)
[   78.486363]  r10:00000006 r9:d7722000 r8:c01011c4 r7:00000000 r6:c0ebac6c r5:d892a340
[   78.501869]  r4:d8a8a280
[   78.512002] [<c02641d4>] (____fput) from [<c013ef1c>] (task_work_run+0x98/0xac)
[   78.527186] [<c013ee84>] (task_work_run) from [<c010cc54>] (do_work_pending+0x4f8/0x570)
[   78.543238]  r7:d7722030 r6:00000004 r5:d7723fb0 r4:00000000
[   78.556825] [<c010c75c>] (do_work_pending) from [<c0101034>] (slow_work_pending+0xc/0x20)
[   78.674256] ---[ end trace 70d3a60cf739be3b ]---

Fix by using drm_fb_helper_lastclose() which checks if fbdev is in use.

Fixes: 9060d7f ("drm/fb-helper: Finish the generic fbdev emulation")
Cc: [email protected]
Signed-off-by: Noralf Trønnes <[email protected]>
Reviewed-by: Gerd Hoffmann <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
anholt pushed a commit that referenced this pull request Feb 20, 2019
In drm_dp_mst_deallocate_vcpi(), we currently unconditionally call
drm_dp_mst_put_port_malloc() on the port that's passed to us, even if we
never successfully allocated VCPI to it. This is contrary to what we do
in drm_dp_mst_allocate_vcpi(), where we only call
drm_dp_mst_get_port_malloc() on the passed port if we successfully
allocated VCPI to it.

As a result, if drm_dp_mst_allocate_vcpi() fails during a modeset and
another successive modeset calls drm_dp_mst_deallocate_vcpi() we will
end up dropping someone else's malloc reference to the port. Example:

[  962.309260] ==================================================================
[  962.309290] BUG: KASAN: use-after-free in drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309296] Read of size 4 at addr ffff888416c30004 by task kworker/0:1H/500

[  962.309308] CPU: 0 PID: 500 Comm: kworker/0:1H Tainted: G        W  O      5.0.0-rc2Lyude-Test+ #1
[  962.309313] Hardware name: LENOVO 20L8S2N800/20L8S2N800, BIOS N22ET35W (1.12 ) 04/09/2018
[  962.309428] Workqueue: events_highpri intel_atomic_cleanup_work [i915]
[  962.309434] Call Trace:
[  962.309452]  dump_stack+0xad/0x150
[  962.309462]  ? dump_stack_print_info.cold.0+0x1b/0x1b
[  962.309472]  ? kmsg_dump_rewind_nolock+0xd9/0xd9
[  962.309504]  ? drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309515]  print_address_description+0x6c/0x23c
[  962.309542]  ? drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309568]  ? drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309577]  kasan_report.cold.3+0x1a/0x32
[  962.309605]  ? drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309631]  drm_dp_mst_put_port_malloc+0x72/0x180 [drm_kms_helper]
[  962.309658]  ? drm_dp_mst_put_mstb_malloc+0x180/0x180 [drm_kms_helper]
[  962.309687]  drm_dp_mst_destroy_state+0xcd/0x120 [drm_kms_helper]
[  962.309745]  drm_atomic_state_default_clear+0x6ee/0xcc0 [drm]
[  962.309864]  intel_atomic_state_clear+0xe/0x80 [i915]
[  962.309928]  __drm_atomic_state_free+0x35/0xd0 [drm]
[  962.310044]  intel_atomic_cleanup_work+0x56/0x70 [i915]
[  962.310057]  process_one_work+0x884/0x1400
[  962.310067]  ? drain_workqueue+0x5a0/0x5a0
[  962.310075]  ? __schedule+0x87f/0x1e80
[  962.310086]  ? __sched_text_start+0x8/0x8
[  962.310095]  ? run_rebalance_domains+0x400/0x400
[  962.310110]  ? deref_stack_reg+0xb4/0x120
[  962.310117]  ? __read_once_size_nocheck.constprop.7+0x10/0x10
[  962.310124]  ? worker_enter_idle+0x47f/0x6a0
[  962.310134]  ? schedule+0xd7/0x2e0
[  962.310141]  ? __schedule+0x1e80/0x1e80
[  962.310148]  ? _raw_spin_lock_irq+0x9f/0x130
[  962.310155]  ? _raw_write_unlock_irqrestore+0x110/0x110
[  962.310164]  worker_thread+0x196/0x11e0
[  962.310175]  ? set_load_weight+0x2e0/0x2e0
[  962.310181]  ? __switch_to_asm+0x34/0x70
[  962.310187]  ? __switch_to_asm+0x40/0x70
[  962.310194]  ? process_one_work+0x1400/0x1400
[  962.310199]  ? __switch_to_asm+0x40/0x70
[  962.310205]  ? __switch_to_asm+0x34/0x70
[  962.310211]  ? __switch_to_asm+0x34/0x70
[  962.310216]  ? __switch_to_asm+0x40/0x70
[  962.310221]  ? __switch_to_asm+0x34/0x70
[  962.310226]  ? __switch_to_asm+0x40/0x70
[  962.310231]  ? __switch_to_asm+0x34/0x70
[  962.310236]  ? __switch_to_asm+0x40/0x70
[  962.310242]  ? syscall_return_via_sysret+0xf/0x7f
[  962.310248]  ? __switch_to_asm+0x34/0x70
[  962.310253]  ? __switch_to_asm+0x40/0x70
[  962.310258]  ? __switch_to_asm+0x34/0x70
[  962.310263]  ? __switch_to_asm+0x40/0x70
[  962.310268]  ? __switch_to_asm+0x34/0x70
[  962.310273]  ? __switch_to_asm+0x40/0x70
[  962.310281]  ? __schedule+0x87f/0x1e80
[  962.310292]  ? __sched_text_start+0x8/0x8
[  962.310300]  ? save_stack+0x8c/0xb0
[  962.310308]  ? __kasan_kmalloc.constprop.6+0xc6/0xd0
[  962.310313]  ? kthread+0x98/0x3a0
[  962.310318]  ? ret_from_fork+0x35/0x40
[  962.310334]  ? __wake_up_common+0x178/0x6f0
[  962.310343]  ? _raw_spin_lock_irqsave+0xa4/0x140
[  962.310349]  ? __lock_text_start+0x8/0x8
[  962.310355]  ? _raw_write_lock_irqsave+0x70/0x130
[  962.310360]  ? __lock_text_start+0x8/0x8
[  962.310371]  ? process_one_work+0x1400/0x1400
[  962.310376]  kthread+0x2e2/0x3a0
[  962.310383]  ? kthread_create_on_node+0xc0/0xc0
[  962.310389]  ret_from_fork+0x35/0x40

[  962.310401] Allocated by task 1462:
[  962.310410]  __kasan_kmalloc.constprop.6+0xc6/0xd0
[  962.310437]  drm_dp_add_port+0xd60/0x1960 [drm_kms_helper]
[  962.310464]  drm_dp_send_link_address+0x4b0/0x770 [drm_kms_helper]
[  962.310491]  drm_dp_check_and_send_link_address+0x197/0x1f0 [drm_kms_helper]
[  962.310515]  drm_dp_mst_link_probe_work+0x2b6/0x330 [drm_kms_helper]
[  962.310522]  process_one_work+0x884/0x1400
[  962.310529]  worker_thread+0x196/0x11e0
[  962.310533]  kthread+0x2e2/0x3a0
[  962.310538]  ret_from_fork+0x35/0x40

[  962.310543] Freed by task 500:
[  962.310550]  __kasan_slab_free+0x133/0x180
[  962.310555]  kfree+0x92/0x1a0
[  962.310581]  drm_dp_mst_put_port_malloc+0x14d/0x180 [drm_kms_helper]
[  962.310693]  intel_connector_destroy+0xb2/0xe0 [i915]
[  962.310747]  drm_mode_object_put.part.0+0x12b/0x1a0 [drm]
[  962.310802]  drm_atomic_state_default_clear+0x1f2/0xcc0 [drm]
[  962.310916]  intel_atomic_state_clear+0xe/0x80 [i915]
[  962.310972]  __drm_atomic_state_free+0x35/0xd0 [drm]
[  962.311083]  intel_atomic_cleanup_work+0x56/0x70 [i915]
[  962.311092]  process_one_work+0x884/0x1400
[  962.311098]  worker_thread+0x196/0x11e0
[  962.311103]  kthread+0x2e2/0x3a0
[  962.311108]  ret_from_fork+0x35/0x40

[  962.311116] The buggy address belongs to the object at ffff888416c30000
                which belongs to the cache kmalloc-2k of size 2048
[  962.311122] The buggy address is located 4 bytes inside of
                2048-byte region [ffff888416c30000, ffff888416c30800)
[  962.311124] The buggy address belongs to the page:
[  962.311132] page:ffffea00105b0c00 count:1 mapcount:0 mapping:ffff88841d003040 index:0x0 compound_mapcount: 0
[  962.311142] flags: 0x8000000000010200(slab|head)
[  962.311152] raw: 8000000000010200 dead000000000100 dead000000000200 ffff88841d003040
[  962.311159] raw: 0000000000000000 00000000000f000f 00000001ffffffff 0000000000000000
[  962.311162] page dumped because: kasan: bad access detected

So, bail early if drm_dp_mst_deallocate_vcpi() is called on a port with
no VCPI allocation. Additionally, clean up the surrounding kerneldoc
while we're at it since the port is assumed to be kept around because
the DRM driver is expected to hold a malloc reference to it, not just
us.

Changes since v1:
* Doc changes - danvet

Signed-off-by: Lyude Paul <[email protected]>
Fixes: eceae14 ("drm/dp_mst: Start tracking per-port VCPI allocations")
Reviewed-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
anholt pushed a commit that referenced this pull request Feb 20, 2019
Since

commit 39b50c6 ("drm/atomic_helper: Stop modesets on unregistered
connectors harder")

We've been failing atomic checks if they try to enable new displays on
unregistered connectors. This is fine except for the one situation that
breaks atomic assumptions: suspend/resume. If a connector is
unregistered before we attempt to restore the atomic state, something we
end up failing the atomic check that happens when trying to restore the
state during resume.

Normally this would be OK: we try our best to make sure that the atomic
state pre-suspend can be restored post-suspend, but failures at that
point usually don't cause problems. That is of course, until we
introduced the new atomic MST VCPI helpers:

[drm:drm_atomic_helper_check_modeset [drm_kms_helper]] [CRTC:65:pipe B] active changed
[drm:drm_atomic_helper_check_modeset [drm_kms_helper]] Updating routing for [CONNECTOR:123:DP-5]
[drm:drm_atomic_helper_check_modeset [drm_kms_helper]] Disabling [CONNECTOR:123:DP-5]
[drm:drm_atomic_get_private_obj_state [drm]] Added new private object 0000000025844636 state 000000009fd2899a to 000000003a13d7b8
WARNING: CPU: 6 PID: 1070 at drivers/gpu/drm/drm_dp_mst_topology.c:3153 drm_dp_atomic_release_vcpi_slots+0xb9/0x200 [drm_kms_helper]
Modules linked in: fuse vfat fat snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic joydev iTCO_wdt i915(O) wmi_bmof intel_rapl btusb btrtl x86_pkg_temp_thermal btbcm btintel coretemp i2c_algo_bit drm_kms_helper(O) crc32_pclmul snd_hda_intel syscopyarea sysfillrect snd_hda_codec sysimgblt snd_hda_core bluetooth fb_sys_fops snd_pcm pcspkr drm(O) psmouse snd_timer mei_me ecdh_generic i2c_i801 mei i2c_core ucsi_acpi typec_ucsi typec wmi thinkpad_acpi ledtrig_audio snd soundcore tpm_tis rfkill tpm_tis_core video tpm acpi_pad pcc_cpufreq uas usb_storage crc32c_intel nvme serio_raw xhci_pci nvme_core xhci_hcd
CPU: 6 PID: 1070 Comm: gnome-shell Tainted: G        W  O      5.0.0-rc2Lyude-Test+ #1
Hardware name: LENOVO 20L8S2N800/20L8S2N800, BIOS N22ET35W (1.12 ) 04/09/2018
RIP: 0010:drm_dp_atomic_release_vcpi_slots+0xb9/0x200 [drm_kms_helper]
Code: 00 4c 39 6d f0 74 49 48 8d 7b 10 48 89 f9 48 c1 e9 03 42 80 3c 21 00 0f 85 d2 00 00 00 48 8b 6b 10 48 8d 5d f0 49 39 ee 75 c5 <0f> 0b 48 c7 c7 c0 78 b3 a0 48 89 c2 4c 89 ee e8 03 6c aa ff b8 ea
RSP: 0018:ffff88841235f268 EFLAGS: 00010246
RAX: ffff88841bf12ab0 RBX: ffff88841bf12aa8 RCX: 1ffff110837e2557
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffffed108246bde0
RBP: ffff88841bf12ab8 R08: ffffed1083db3c93 R09: ffffed1083db3c92
R10: ffffed1083db3c92 R11: ffff88841ed9e497 R12: ffff888419555d80
R13: ffff8883bc499100 R14: ffff88841bf12ab8 R15: 0000000000000000
FS:  00007f16fbd4cd00(0000) GS:ffff88841ed80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1687c9f000 CR3: 00000003ba3cc003 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 drm_atomic_helper_check_modeset+0xf21/0x2f50 [drm_kms_helper]
 ? drm_atomic_helper_commit_modeset_enables+0xa90/0xa90 [drm_kms_helper]
 ? __printk_safe_exit+0x10/0x10
 ? save_stack+0x8c/0xb0
 ? vprintk_func+0x96/0x1bf
 ? __printk_safe_exit+0x10/0x10
 intel_atomic_check+0x234/0x4750 [i915]
 ? printk+0x9f/0xc5
 ? kmsg_dump_rewind_nolock+0xd9/0xd9
 ? _raw_spin_lock_irqsave+0xa4/0x140
 ? drm_atomic_check_only+0xb1/0x28b0 [drm]
 ? drm_dbg+0x186/0x1b0 [drm]
 ? drm_dev_dbg+0x200/0x200 [drm]
 ? intel_link_compute_m_n+0xb0/0xb0 [i915]
 ? drm_mode_put_tile_group+0x20/0x20 [drm]
 ? skl_plane_format_mod_supported+0x17f/0x1b0 [i915]
 ? drm_plane_check_pixel_format+0x14a/0x310 [drm]
 drm_atomic_check_only+0x13c4/0x28b0 [drm]
 ? drm_state_info+0x220/0x220 [drm]
 ? drm_atomic_helper_disable_plane+0x1d0/0x1d0 [drm_kms_helper]
 ? pick_single_encoder_for_connector+0xe0/0xe0 [drm_kms_helper]
 ? kasan_unpoison_shadow+0x35/0x40
 drm_atomic_commit+0x3b/0x100 [drm]
 drm_atomic_helper_set_config+0xd5/0x100 [drm_kms_helper]
 drm_mode_setcrtc+0x636/0x1660 [drm]
 ? vprintk_func+0x96/0x1bf
 ? drm_dev_dbg+0x200/0x200 [drm]
 ? drm_mode_getcrtc+0x790/0x790 [drm]
 ? printk+0x9f/0xc5
 ? mutex_unlock+0x1d/0x40
 ? drm_mode_addfb2+0x2e9/0x3a0 [drm]
 ? rcu_sync_dtor+0x2e0/0x2e0
 ? drm_dbg+0x186/0x1b0 [drm]
 ? set_page_dirty+0x271/0x4d0
 drm_ioctl_kernel+0x203/0x290 [drm]
 ? drm_mode_getcrtc+0x790/0x790 [drm]
 ? drm_setversion+0x7f0/0x7f0 [drm]
 ? __switch_to_asm+0x34/0x70
 ? __switch_to_asm+0x34/0x70
 drm_ioctl+0x445/0x950 [drm]
 ? drm_mode_getcrtc+0x790/0x790 [drm]
 ? drm_getunique+0x220/0x220 [drm]
 ? expand_files.part.10+0x920/0x920
 do_vfs_ioctl+0x1a1/0x13d0
 ? ioctl_preallocate+0x2b0/0x2b0
 ? __fget_light+0x2d6/0x390
 ? schedule+0xd7/0x2e0
 ? fget_raw+0x10/0x10
 ? apic_timer_interrupt+0xa/0x20
 ? apic_timer_interrupt+0xa/0x20
 ? rcu_cleanup_dead_rnp+0x2c0/0x2c0
 ksys_ioctl+0x60/0x90
 __x64_sys_ioctl+0x6f/0xb0
 do_syscall_64+0x136/0x440
 ? syscall_return_slowpath+0x2d0/0x2d0
 ? do_page_fault+0x89/0x330
 ? __do_page_fault+0x9c0/0x9c0
 ? prepare_exit_to_usermode+0x188/0x200
 ? perf_trace_sys_enter+0x1090/0x1090
 ? __x64_sys_sigaltstack+0x280/0x280
 ? __put_user_4+0x1c/0x30
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f16ff89a09b
Code: 0f 1e fa 48 8b 05 ed bd 0c 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d bd bd 0c 00 f7 d8 64 89 01 48
RSP: 002b:00007fff001232b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff001232f0 RCX: 00007f16ff89a09b
RDX: 00007fff001232f0 RSI: 00000000c06864a2 RDI: 000000000000000b
RBP: 00007fff001232f0 R08: 0000000000000000 R09: 000055a79d484460
R10: 000055a79d44e770 R11: 0000000000000246 R12: 00000000c06864a2
R13: 000000000000000b R14: 0000000000000000 R15: 000055a79d44e770
WARNING: CPU: 6 PID: 1070 at drivers/gpu/drm/drm_dp_mst_topology.c:3153 drm_dp_atomic_release_vcpi_slots+0xb9/0x200 [drm_kms_helper]
---[ end trace d536c05c13c83be2 ]---
[drm:drm_dp_atomic_release_vcpi_slots [drm_kms_helper]] *ERROR* no VCPI for [MST PORT:00000000f9e2b143] found in mst state 000000009fd2899a

This appears to be happening because we destroy the VCPI allocations
when disabling all connected displays while suspending, and those VCPI
allocations don't get restored on resume due to failing to restore the
atomic state.

So, fix this by introducing the suspending option to
drm_atomic_helper_duplicate_state() and use that to indicate in the
atomic state that it's being used for suspending or resuming the system,
and thus needs to be fixed up by the driver. We can then use the new
state->duplicated hook to tell update_connector_routing() in
drm_atomic_check_modeset() to allow for modesets on unregistered
connectors, which allows us to restore atomic states that contain MST
topologies that were removed after the state was duplicated and thus:
mostly fixing suspend and resume. This just leaves some issues that were
introduced with nouveau, that will be addressed next.

Changes since v3:
* Remove ->duplicated hunks that I left in the VCPI helpers by accident.
  These don't need to be here, that was the supposed to be the purpose
  of the last revision
Changes since v2:
* Remove the changes in this patch to the VCPI helpers, they aren't
  needed anymore
Changes since v1:
* Rename suspend_or_resume to duplicated

Signed-off-by: Lyude Paul <[email protected]>
Fixes: eceae14 ("drm/dp_mst: Start tracking per-port VCPI allocations")
Cc: Daniel Vetter <[email protected]>
Reviewed-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
lategoodbye pushed a commit that referenced this pull request May 25, 2019
kernel BUG at lib/list_debug.c:47!
invalid opcode: 0000 [#1
CPU: 0 PID: 12914 Comm: rmmod Tainted: G        W         5.1.0+ #47
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
RIP: 0010:__list_del_entry_valid+0x53/0x90
Code: 48 8b 32 48 39 fe 75 35 48 8b 50 08 48 39 f2 75 40 b8 01 00 00 00 5d c3 48
89 fe 48 89 c2 48 c7 c7 18 75 fe 82 e8 cb 34 78 ff <0f> 0b 48 89 fe 48 c7 c7 50 75 fe 82 e8 ba 34 78 ff 0f 0b 48 89 f2
RSP: 0018:ffffc90001c2fe40 EFLAGS: 00010286
RAX: 000000000000004e RBX: ffffffffa0184000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff888237a17788 RDI: 00000000ffffffff
RBP: ffffc90001c2fe40 R08: 0000000000000000 R09: 0000000000000000
R10: ffffc90001c2fe10 R11: 0000000000000000 R12: 0000000000000000
R13: ffffc90001c2fe50 R14: ffffffffa0184000 R15: 0000000000000000
FS:  00007f3d83634540(0000) GS:ffff888237a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555c350ea818 CR3: 0000000231677000 CR4: 00000000000006f0
Call Trace:
 unregister_pernet_operations+0x34/0x120
 unregister_pernet_subsys+0x1c/0x30
 packet_exit+0x1c/0x369 [af_packet
 __x64_sys_delete_module+0x156/0x260
 ? lockdep_hardirqs_on+0x133/0x1b0
 ? do_syscall_64+0x12/0x1f0
 do_syscall_64+0x6e/0x1f0
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

When modprobe af_packet, register_pernet_subsys
fails and does a cleanup, ops->list is set to LIST_POISON1,
but the module init is considered to success, then while rmmod it,
BUG() is triggered in __list_del_entry_valid which is called from
unregister_pernet_subsys. This patch fix error handing path in
packet_init to avoid possilbe issue if some error occur.

Reported-by: Hulk Robot <[email protected]>
Signed-off-by: YueHaibing <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
systemtap folks reported the following splat recently:

  [ 7790.862212] WARNING: CPU: 3 PID: 26759 at arch/x86/kernel/kprobes/core.c:1022 kprobe_fault_handler+0xec/0xf0
  [...]
  [ 7790.864113] CPU: 3 PID: 26759 Comm: sshd Not tainted 5.1.0-0.rc7.git1.1.fc31.x86_64 #1
  [ 7790.864198] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS[...]
  [ 7790.864314] RIP: 0010:kprobe_fault_handler+0xec/0xf0
  [ 7790.864375] Code: 48 8b 50 [...]
  [ 7790.864714] RSP: 0018:ffffc06800bdbb48 EFLAGS: 00010082
  [ 7790.864812] RAX: ffff9e2b75a16320 RBX: 0000000000000000 RCX: 0000000000000000
  [ 7790.865306] RDX: ffffffffffffffff RSI: 000000000000000e RDI: ffffc06800bdbbf8
  [ 7790.865514] RBP: ffffc06800bdbbf8 R08: 0000000000000000 R09: 0000000000000000
  [ 7790.865960] R10: 0000000000000000 R11: 0000000000000000 R12: ffffc06800bdbbf8
  [ 7790.866037] R13: ffff9e2ab56a0418 R14: ffff9e2b6d0bb400 R15: ffff9e2b6d268000
  [ 7790.866114] FS:  00007fde49937d80(0000) GS:ffff9e2b75a00000(0000) knlGS:0000000000000000
  [ 7790.866193] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [ 7790.866318] CR2: 0000000000000000 CR3: 000000012f312000 CR4: 00000000000006e0
  [ 7790.866419] Call Trace:
  [ 7790.866677]  do_user_addr_fault+0x64/0x480
  [ 7790.867513]  do_page_fault+0x33/0x210
  [ 7790.868002]  async_page_fault+0x1e/0x30
  [ 7790.868071] RIP: 0010:          (null)
  [ 7790.868144] Code: Bad RIP value.
  [ 7790.868229] RSP: 0018:ffffc06800bdbca8 EFLAGS: 00010282
  [ 7790.868362] RAX: ffff9e2b598b60f8 RBX: ffffc06800bdbe48 RCX: 0000000000000004
  [ 7790.868629] RDX: 0000000000000004 RSI: ffffc06800bdbc6c RDI: ffff9e2b598b60f0
  [ 7790.868834] RBP: ffffc06800bdbcf8 R08: 0000000000000000 R09: 0000000000000004
  [ 7790.870432] R10: 00000000ff6f7a03 R11: 0000000000000000 R12: 0000000000000001
  [ 7790.871859] R13: ffffc06800bdbcb8 R14: 0000000000000000 R15: ffff9e2acd0a5310
  [ 7790.873455]  ? vfs_read+0x5/0x170
  [ 7790.874639]  ? vfs_read+0x1/0x170
  [ 7790.875834]  ? trace_call_bpf+0xf6/0x260
  [ 7790.877044]  ? vfs_read+0x1/0x170
  [ 7790.878208]  ? vfs_read+0x5/0x170
  [ 7790.879345]  ? kprobe_perf_func+0x233/0x260
  [ 7790.880503]  ? vfs_read+0x1/0x170
  [ 7790.881632]  ? vfs_read+0x5/0x170
  [ 7790.882751]  ? kprobe_ftrace_handler+0x92/0xf0
  [ 7790.883926]  ? __vfs_read+0x30/0x30
  [ 7790.885050]  ? ftrace_ops_assist_func+0x94/0x100
  [ 7790.886183]  ? vfs_read+0x1/0x170
  [ 7790.887283]  ? vfs_read+0x5/0x170
  [ 7790.888348]  ? ksys_read+0x5a/0xe0
  [ 7790.889389]  ? do_syscall_64+0x5c/0xa0
  [ 7790.890401]  ? entry_SYSCALL_64_after_hwframe+0x49/0xbe

After some debugging, turns out that the logic in 2cbd95a
("bpf: change parameters of call/branch offset adjustment") has
a bug that is exposed after 52875a0 ("bpf: verifier: remove
dead code") in that we miss some of the jump offset adjustments
after code patching when we remove dead code, more concretely,
upon backward jump spanning over the area that is being removed.

BPF insns of a case that was hit pre 52875a0:

  [...]
  676: (85) call bpf_perf_event_output#-47616
  677: (05) goto pc-636
  678: (62) *(u32 *)(r10 -64) = 0
  679: (bf) r7 = r10
  680: (07) r7 += -64
  681: (05) goto pc-44
  682: (05) goto pc-1
  683: (05) goto pc-1

BPF insns afterwards:

  [...]
  618: (85) call bpf_perf_event_output#-47616
  619: (05) goto pc-638
  620: (62) *(u32 *)(r10 -64) = 0
  621: (bf) r7 = r10
  622: (07) r7 += -64
  623: (05) goto pc-44

To illustrate the bug, situation looks as follows:
     ____
  0 |    | <-- foo: [...]
  1 |____|
  2 |____| <-- pos / end_new  ^
  3 |    |                    |
  4 |    |                    |  len
  5 |____|                    |  (remove region)
  6 |    | <-- end_old        v
  7 |    |
  8 |    | <-- curr  (jmp foo)
  9 |____|

The condition curr >= end_new && curr + off + 1 < end_new in the
branch delta adjustments is never hit because curr + off + 1 <
end_new is compared as unsigned and therefore curr + off + 1 >
end_new in unsigned realm as curr + off + 1 becomes negative
since the insns are memmove()'d before the offset adjustments.

Correct BPF insns after this fix:

  [...]
  618: (85) call bpf_perf_event_output#-47216
  619: (05) goto pc-578
  620: (62) *(u32 *)(r10 -64) = 0
  621: (bf) r7 = r10
  622: (07) r7 += -64
  623: (05) goto pc-44

Note that unprivileged case is not affected from this.

Fixes: 52875a0 ("bpf: verifier: remove dead code")
Fixes: 2cbd95a ("bpf: change parameters of call/branch offset adjustment")
Reported-by: Frank Ch. Eigler <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Reviewed-by: Jakub Kicinski <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
Various things in eBPF really require us to disable preemption
before running an eBPF program.

syzbot reported :

BUG: assuming atomic context at net/core/flow_dissector.c:737
in_atomic(): 0, irqs_disabled(): 0, pid: 24710, name: syz-executor.3
2 locks held by syz-executor.3/24710:
 #0: 00000000e81a4bf1 (&tfile->napi_mutex){+.+.}, at: tun_get_user+0x168e/0x3ff0 drivers/net/tun.c:1850
 #1: 00000000254afebd (rcu_read_lock){....}, at: __skb_flow_dissect+0x1e1/0x4bb0 net/core/flow_dissector.c:822
CPU: 1 PID: 24710 Comm: syz-executor.3 Not tainted 5.1.0+ #6
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 __cant_sleep kernel/sched/core.c:6165 [inline]
 __cant_sleep.cold+0xa3/0xbb kernel/sched/core.c:6142
 bpf_flow_dissect+0xfe/0x390 net/core/flow_dissector.c:737
 __skb_flow_dissect+0x362/0x4bb0 net/core/flow_dissector.c:853
 skb_flow_dissect_flow_keys_basic include/linux/skbuff.h:1322 [inline]
 skb_probe_transport_header include/linux/skbuff.h:2500 [inline]
 skb_probe_transport_header include/linux/skbuff.h:2493 [inline]
 tun_get_user+0x2cfe/0x3ff0 drivers/net/tun.c:1940
 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037
 call_write_iter include/linux/fs.h:1872 [inline]
 do_iter_readv_writev+0x5fd/0x900 fs/read_write.c:693
 do_iter_write fs/read_write.c:970 [inline]
 do_iter_write+0x184/0x610 fs/read_write.c:951
 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015
 do_writev+0x15b/0x330 fs/read_write.c:1058
 __do_sys_writev fs/read_write.c:1131 [inline]
 __se_sys_writev fs/read_write.c:1128 [inline]
 __x64_sys_writev+0x75/0xb0 fs/read_write.c:1128
 do_syscall_64+0x103/0x670 arch/x86/entry/common.c:298
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Fixes: d58e468 ("flow_dissector: implements flow dissector BPF hook")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Petar Penkov <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
…ed addresses

Starting with c6f3c5e ("mm/huge_memory.c: fix modifying of page
protection by insert_pfn_pmd()") vmf_insert_pfn_pmd() internally calls
pmdp_set_access_flags().  That helper enforces a pmd aligned @address
argument via VM_BUG_ON() assertion.

Update the implementation to take a 'struct vm_fault' argument directly
and apply the address alignment fixup internally to fix crash signatures
like:

    kernel BUG at arch/x86/mm/pgtable.c:515!
    invalid opcode: 0000 [#1] SMP NOPTI
    CPU: 51 PID: 43713 Comm: java Tainted: G           OE     4.19.35 #1
    [..]
    RIP: 0010:pmdp_set_access_flags+0x48/0x50
    [..]
    Call Trace:
     vmf_insert_pfn_pmd+0x198/0x350
     dax_iomap_fault+0xe82/0x1190
     ext4_dax_huge_fault+0x103/0x1f0
     ? __switch_to_asm+0x40/0x70
     __handle_mm_fault+0x3f6/0x1370
     ? __switch_to_asm+0x34/0x70
     ? __switch_to_asm+0x40/0x70
     handle_mm_fault+0xda/0x200
     __do_page_fault+0x249/0x4f0
     do_page_fault+0x32/0x110
     ? page_fault+0x8/0x30
     page_fault+0x1e/0x30

Link: http://lkml.kernel.org/r/155741946350.372037.11148198430068238140.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: c6f3c5e ("mm/huge_memory.c: fix modifying of page protection by insert_pfn_pmd()")
Signed-off-by: Dan Williams <[email protected]>
Reported-by: Piotr Balcer <[email protected]>
Tested-by: Yan Ma <[email protected]>
Tested-by: Pankaj Gupta <[email protected]>
Reviewed-by: Matthew Wilcox <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
Cc: Chandan Rajendra <[email protected]>
Cc: Souptick Joarder <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
The following warning is seen on systems with broken clock divider.

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 0 PID: 1 Comm: swapper Not tainted 5.1.0-09698-g1fb3b52 #1
Hardware name: ARM Integrator/CP (Device Tree)
[<c0011be8>] (unwind_backtrace) from [<c000ebb8>] (show_stack+0x10/0x18)
[<c000ebb8>] (show_stack) from [<c07d3fd0>] (dump_stack+0x18/0x24)
[<c07d3fd0>] (dump_stack) from [<c0060d48>] (register_lock_class+0x674/0x6f8)
[<c0060d48>] (register_lock_class) from [<c005de2c>]
	(__lock_acquire+0x68/0x2128)
[<c005de2c>] (__lock_acquire) from [<c0060408>] (lock_acquire+0x110/0x21c)
[<c0060408>] (lock_acquire) from [<c07f755c>] (_raw_spin_lock+0x34/0x48)
[<c07f755c>] (_raw_spin_lock) from [<c0536c8c>]
	(pl111_display_enable+0xf8/0x5fc)
[<c0536c8c>] (pl111_display_enable) from [<c0502f54>]
	(drm_atomic_helper_commit_modeset_enables+0x1ec/0x244)

Since commit eedd603 ("drm/pl111: Support variants with broken clock
divider"), the spinlock is not initialized if the clock divider is broken.
Initialize it earlier to fix the problem.

Fixes: eedd603 ("drm/pl111: Support variants with broken clock divider")
Cc: Linus Walleij <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Linus Walleij <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
lategoodbye pushed a commit that referenced this pull request May 25, 2019
The recent commit to cleanup ifdefs in the hugepage initialisation led
to crashes when using 4K pages as reported by Sachin:

  BUG: Kernel NULL pointer dereference at 0x0000001c
  Faulting instruction address: 0xc000000001d1e58c
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  ...
  CPU: 3 PID: 4635 Comm: futex_wake04 Tainted: G        W  O      5.1.0-next-20190507-autotest #1
  NIP:  c000000001d1e58c LR: c000000001d1e54c CTR: 0000000000000000
  REGS: c000000004937890 TRAP: 0300
  MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 2242482  XER: 00000000
  CFAR: c00000000183e9e0 DAR: 000000000000001c DSISR: 40000000 IRQMASK: 0
  ...
  NIP kmem_cache_alloc+0xbc/0x5a0
  LR  kmem_cache_alloc+0x7c/0x5a0
  Call Trace:
    huge_pte_alloc+0x580/0x950
    hugetlb_fault+0x9a0/0x1250
    handle_mm_fault+0x490/0x4a0
    __do_page_fault+0x77c/0x1f00
    do_page_fault+0x28/0x50
    handle_page_fault+0x18/0x38

This is caused by us trying to allocate from a NULL kmem cache in
__hugepte_alloc(). The kmem cache is NULL because it was never
allocated in hugetlbpage_init(), because add_huge_page_size() returned
an error.

The reason add_huge_page_size() returned an error is a simple typo, we
are calling check_and_get_huge_psize(size) when we should be passing
shift instead.

The fact that we're able to trigger this path when the kmem caches are
NULL is a separate bug, ie. we should not advertise any hugepage sizes
if we haven't setup the required caches for them.

This was only seen with 4K pages, with 64K pages we don't need to
allocate any extra kmem caches because the 16M hugepage just occupies
a single entry at the PMD level.

Fixes: 723f268 ("powerpc/mm: cleanup ifdef mess in add_huge_page_size()")
Reported-by: Sachin Sant <[email protected]>
Tested-by: Sachin Sant <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Reviewed-by: Christophe Leroy <[email protected]>
Reviewed-by: Aneesh Kumar K.V <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
Patch series "lib/sort & lib/list_sort: faster and smaller", v2.

Because CONFIG_RETPOLINE has made indirect calls much more expensive, I
thought I'd try to reduce the number made by the library sort functions.

The first three patches apply to lib/sort.c.

Patch #1 is a simple optimization.  The built-in swap has special cases
for aligned 4- and 8-byte objects.  But those are almost never used;
most calls to sort() work on larger structures, which fall back to the
byte-at-a-time loop.  This generalizes them to aligned *multiples* of 4
and 8 bytes.  (If nothing else, it saves an awful lot of energy by not
thrashing the store buffers as much.)

Patch #2 grabs a juicy piece of low-hanging fruit.  I agree that nice
simple solid heapsort is preferable to more complex algorithms (sorry,
Andrey), but it's possible to implement heapsort with far fewer
comparisons (50% asymptotically, 25-40% reduction for realistic sizes)
than the way it's been done up to now.  And with some care, the code
ends up smaller, as well.  This is the "big win" patch.

Patch #3 adds the same sort of indirect call bypass that has been added
to the net code of late.  The great majority of the callers use the
builtin swap functions, so replace the indirect call to sort_func with a
(highly preditable) series of if() statements.  Rather surprisingly,
this decreased code size, as the swap functions were inlined and their
prologue & epilogue code eliminated.

lib/list_sort.c is a bit trickier, as merge sort is already close to
optimal, and we don't want to introduce triumphs of theory over
practicality like the Ford-Johnson merge-insertion sort.

Patch #4, without changing the algorithm, chops 32% off the code size
and removes the part[MAX_LIST_LENGTH+1] pointer array (and the
corresponding upper limit on efficiently sortable input size).

Patch #5 improves the algorithm.  The previous code is already optimal
for power-of-two (or slightly smaller) size inputs, but when the input
size is just over a power of 2, there's a very unbalanced final merge.

There are, in the literature, several algorithms which solve this, but
they all depend on the "breadth-first" merge order which was replaced by
commit 835cc0c with a more cache-friendly "depth-first" order.
Some hard thinking came up with a depth-first algorithm which defers
merges as little as possible while avoiding bad merges.  This saves
0.2*n compares, averaged over all sizes.

The code size increase is minimal (64 bytes on x86-64, reducing the net
savings to 26%), but the comments expanded significantly to document the
clever algorithm.

TESTING NOTES: I have some ugly user-space benchmarking code which I
used for testing before moving this code into the kernel.  Shout if you
want a copy.

I'm running this code right now, with CONFIG_TEST_SORT and
CONFIG_TEST_LIST_SORT, but I confess I haven't rebooted since the last
round of minor edits to quell checkpatch.  I figure there will be at
least one round of comments and final testing.

This patch (of 5):

Rather than having special-case swap functions for 4- and 8-byte
objects, special-case aligned multiples of 4 or 8 bytes.  This speeds up
most users of sort() by avoiding fallback to the byte copy loop.

Despite what ca96ab8 ("lib/sort: Add 64 bit swap function") claims,
very few users of sort() sort pointers (or pointer-sized objects); most
sort structures containing at least two words.  (E.g.
drivers/acpi/fan.c:acpi_fan_get_fps() sorts an array of 40-byte struct
acpi_fan_fps.)

The functions also got renamed to reflect the fact that they support
multiple words.  In the great tradition of bikeshedding, the names were
by far the most contentious issue during review of this patch series.

x86-64 code size 872 -> 886 bytes (+14)

With feedback from Andy Shevchenko, Rasmus Villemoes and Geert
Uytterhoeven.

Link: http://lkml.kernel.org/r/f24f932df3a7fa1973c1084154f1cea596bcf341.1552704200.git.lkml@sdf.org
Signed-off-by: George Spelvin <[email protected]>
Acked-by: Andrey Abramov <[email protected]>
Acked-by: Rasmus Villemoes <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Cc: Rasmus Villemoes <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Daniel Wagner <[email protected]>
Cc: Don Mullis <[email protected]>
Cc: Dave Chinner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
We call get_region_id() without validating the ea value. That means
with a wrong ea value we hit the BUG as below.

  kernel BUG at arch/powerpc/include/asm/book3s/64/hash.h:129!
  Oops: Exception in kernel mode, sig: 5 [#1]
  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  CPU: 0 PID: 3937 Comm: access_tests Not tainted 5.1.0
  ....
  NIP [c00000000007ba20] do_slb_fault+0x70/0x320
  LR [c00000000000896c] data_access_slb_common+0x15c/0x1a0

Fix this by removing the VM_BUG_ON. All callers make sure the returned
region id is valid and error out otherwise.

Fixes: 0034d39 ("powerpc/mm/hash64: Map all the kernel regions in the same 0xc range")
Reported-by: Andrew Donnellan <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
lategoodbye pushed a commit that referenced this pull request May 25, 2019
…from a pageblock

syzbot reported the following error from a tree with a head commit of
baf76f0 ("slip: make slhc_free() silently accept an error pointer")

  BUG: unable to handle kernel paging request at ffffea0003348000
  #PF error: [normal kernel read fault]
  PGD 12c3f9067 P4D 12c3f9067 PUD 12c3f8067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 28916 Comm: syz-executor.2 Not tainted 5.1.0-rc6+ #89
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline]
  RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline]
  RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579
  Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38 ff
  ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31 ff 49
  c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff
  RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246
  RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000
  RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001
  RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000
  R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000
  FS:  00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0
  Call Trace:
   fast_isolate_around mm/compaction.c:1243 [inline]
   fast_isolate_freepages mm/compaction.c:1418 [inline]
   isolate_freepages mm/compaction.c:1438 [inline]
   compaction_alloc+0x1aee/0x22e0 mm/compaction.c:1550

There is no reproducer and it is difficult to hit -- 1 crash every few
days.  The issue is very similar to the fix in commit 6b0868c
("mm/compaction.c: correct zone boundary handling when resetting pageblock
skip hints").  When isolating free pages around a target pageblock, the
boundary handling is off by one and can stray into the next pageblock.
Triggering the syzbot error requires that the end of pageblock is section
or zone aligned, and that the next section is unpopulated.

A more subtle consequence of the bug is that pageblocks were being
improperly used as migration targets which potentially hurts fragmentation
avoidance in the long-term one page at a time.

A debugging patch revealed that it's definitely possible to stray outside
of a pageblock which is not intended.  While syzbot cannot be used to
verify this patch, it was confirmed that the debugging warning no longer
triggers with this patch applied.  It has also been confirmed that the THP
allocation stress tests are not degraded by this patch.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: e332f74 ("mm, compaction: be selective about what pageblocks to clear skip hints")
Signed-off-by: Mel Gorman <[email protected]>
Reported-by: [email protected]
Cc: Dmitry Vyukov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Qian Cai <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: <[email protected]> # v5.1+
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Observe a segmentation fault when 'perf stat' is asked to repeat forever
with the interval option.

Without fix:

  # perf stat -r 0 -I 5000 -e cycles -a sleep 10
  #           time             counts unit events
       5.000211692  3,13,89,82,34,157      cycles
      10.000380119  1,53,98,52,22,294      cycles
      10.040467280       17,16,79,265      cycles
  Segmentation fault

This problem was only observed when we use forever option aka -r 0 and
works with limited repeats. Calling print_counter with ts being set to
NULL, is not a correct option when interval is set. Hence avoid
print_counter(NULL,..)  if interval is set.

With fix:

  # perf stat -r 0 -I 5000 -e cycles -a sleep 10
   #           time             counts unit events
       5.019866622  3,15,14,43,08,697      cycles
      10.039865756  3,15,16,31,95,261      cycles
      10.059950628     1,26,05,47,158      cycles
       5.009902655  3,14,52,62,33,932      cycles
      10.019880228  3,14,52,22,89,154      cycles
      10.030543876       66,90,18,333      cycles
       5.009848281  3,14,51,98,25,437      cycles
      10.029854402  3,15,14,93,04,918      cycles
       5.009834177  3,14,51,95,92,316      cycles

Committer notes:

Did the 'git bisect' to find the cset introducing the problem to add the
Fixes tag below, and at that time the problem reproduced as:

  (gdb) run stat -r0 -I500 sleep 1
  <SNIP>
  Program received signal SIGSEGV, Segmentation fault.
  print_interval (prefix=prefix@entry=0x7fffffffc8d0 "", ts=ts@entry=0x0) at builtin-stat.c:866
  866		sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, csv_sep);
  (gdb) bt
  #0  print_interval (prefix=prefix@entry=0x7fffffffc8d0 "", ts=ts@entry=0x0) at builtin-stat.c:866
  #1  0x000000000041860a in print_counters (ts=ts@entry=0x0, argc=argc@entry=2, argv=argv@entry=0x7fffffffd640) at builtin-stat.c:938
  #2  0x0000000000419a7f in cmd_stat (argc=2, argv=0x7fffffffd640, prefix=<optimized out>) at builtin-stat.c:1411
  #3  0x000000000045c65a in run_builtin (p=p@entry=0x6291b8 <commands+216>, argc=argc@entry=5, argv=argv@entry=0x7fffffffd640) at perf.c:370
  #4  0x000000000045c893 in handle_internal_command (argc=5, argv=0x7fffffffd640) at perf.c:429
  #5  0x000000000045c8f1 in run_argv (argcp=argcp@entry=0x7fffffffd4ac, argv=argv@entry=0x7fffffffd4a0) at perf.c:473
  #6  0x000000000045cac9 in main (argc=<optimized out>, argv=<optimized out>) at perf.c:588
  (gdb)

Mostly the same as just before this patch:

  Program received signal SIGSEGV, Segmentation fault.
  0x00000000005874a7 in print_interval (config=0xa1f2a0 <stat_config>, evlist=0xbc9b90, prefix=0x7fffffffd1c0 "`", ts=0x0) at util/stat-display.c:964
  964		sprintf(prefix, "%6lu.%09lu%s", ts->tv_sec, ts->tv_nsec, config->csv_sep);
  (gdb) bt
  #0  0x00000000005874a7 in print_interval (config=0xa1f2a0 <stat_config>, evlist=0xbc9b90, prefix=0x7fffffffd1c0 "`", ts=0x0) at util/stat-display.c:964
  #1  0x0000000000588047 in perf_evlist__print_counters (evlist=0xbc9b90, config=0xa1f2a0 <stat_config>, _target=0xa1f0c0 <target>, ts=0x0, argc=2, argv=0x7fffffffd670)
      at util/stat-display.c:1172
  #2  0x000000000045390f in print_counters (ts=0x0, argc=2, argv=0x7fffffffd670) at builtin-stat.c:656
  #3  0x0000000000456bb5 in cmd_stat (argc=2, argv=0x7fffffffd670) at builtin-stat.c:1960
  #4  0x00000000004dd2e0 in run_builtin (p=0xa30e00 <commands+288>, argc=5, argv=0x7fffffffd670) at perf.c:310
  #5  0x00000000004dd54d in handle_internal_command (argc=5, argv=0x7fffffffd670) at perf.c:362
  #6  0x00000000004dd694 in run_argv (argcp=0x7fffffffd4cc, argv=0x7fffffffd4c0) at perf.c:406
  #7  0x00000000004dda11 in main (argc=5, argv=0x7fffffffd670) at perf.c:531
  (gdb)

Fixes: d4f63a4 ("perf stat: Introduce print_counters function")
Signed-off-by: Srikar Dronamraju <[email protected]>
Acked-by: Jiri Olsa <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Tested-by: Ravi Bangoria <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: [email protected] # v4.2+
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
We release wrong pointer on error path in cpu_cache_level__read
function, leading to segfault:

  (gdb) r record ls
  Starting program: /root/perf/tools/perf/perf record ls
  ...
  [ perf record: Woken up 1 times to write data ]
  double free or corruption (out)

  Thread 1 "perf" received signal SIGABRT, Aborted.
  0x00007ffff7463798 in raise () from /lib64/power9/libc.so.6
  (gdb) bt
  #0  0x00007ffff7463798 in raise () from /lib64/power9/libc.so.6
  #1  0x00007ffff7443bac in abort () from /lib64/power9/libc.so.6
  #2  0x00007ffff74af8bc in __libc_message () from /lib64/power9/libc.so.6
  #3  0x00007ffff74b92b8 in malloc_printerr () from /lib64/power9/libc.so.6
  #4  0x00007ffff74bb874 in _int_free () from /lib64/power9/libc.so.6
  #5  0x0000000010271260 in __zfree (ptr=0x7fffffffa0b0) at ../../lib/zalloc..
  #6  0x0000000010139340 in cpu_cache_level__read (cache=0x7fffffffa090, cac..
  #7  0x0000000010143c90 in build_caches (cntp=0x7fffffffa118, size=<optimiz..
  ...

Releasing the proper pointer.

Fixes: 720e98b ("perf tools: Add perf data cache feature")
Signed-off-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]: # v4.6+
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Uncompressing Kernel Image ... OK
   Loading Device Tree to 01ff7000, end 01fff74f ... OK
[    0.000000] printk: bootconsole [udbg0] enabled
[    0.000000] BUG: Unable to handle kernel data access at 0xf818c000
[    0.000000] Faulting instruction address: 0xc0013c7c
[    0.000000] Thread overran stack, or stack corrupted
[    0.000000] Oops: Kernel access of bad area, sig: 11 [#1]
[    0.000000] BE PAGE_SIZE=16K PREEMPT
[    0.000000] Modules linked in:
[    0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty raspberrypi#2080
[    0.000000] NIP:  c0013c7c LR: c0013310 CTR: 00000000
[    0.000000] REGS: c0c5ff38 TRAP: 0300   Not tainted  (5.3.0-rc4-s3k-dev-00743-g5abe4a3e8fd3-dirty)
[    0.000000] MSR:  00001032 <ME,IR,DR,RI>  CR: 99033955  XER: 80002100
[    0.000000] DAR: f818c000 DSISR: 82000000
[    0.000000] GPR00: c0013310 c0c5fff0 c0ad6ac0 c0c600c0 f818c031 82000000 00000000 ffffffff
[    0.000000] GPR08: 00000000 f1f1f1f1 c0013c2c c0013304 99033955 00400008 00000000 07ff9598
[    0.000000] GPR16: 00000000 07ffb94c 00000000 00000000 00000000 00000000 00000000 f818cfb2
[    0.000000] GPR24: 00000000 00000000 00001000 ffffffff 00000000 c07dbf80 00000000 f818c000
[    0.000000] NIP [c0013c7c] do_page_fault+0x50/0x904
[    0.000000] LR [c0013310] handle_page_fault+0xc/0x38
[    0.000000] Call Trace:
[    0.000000] Instruction dump:
[    0.000000] be010080 91410014 553fe8fe 3d40c001 3d20f1f1 7d800026 394a3c2c 3fffe000
[    0.000000] 6129f1f1 900100c4 9181007c 91410018 <913f0000> 3d2001f4 6129f4f4 913f0004

Don't map the early shadow page read-only yet when creating the new
page tables for the real shadow memory, otherwise the memblock
allocations that immediately follows to create the real shadow pages
that are about to replace the early shadow page trigger a page fault
if they fall into the region being worked on at the moment.

Signed-off-by: Christophe Leroy <[email protected]>
Fixes: 2edb16e ("powerpc/32: Add KASAN support")
Cc: [email protected]
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/fe86886fb8db44360417cee0dc515ad47ca6ef72.1566382750.git.christophe.leroy@c-s.fr
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
On a 2-socket Power9 system with 32 cores/128 threads (SMT4) and 1TB
of memory running the following guest configs:

  guest A:
    - 224GB of memory
    - 56 VCPUs (sockets=1,cores=28,threads=2), where:
      VCPUs 0-1 are pinned to CPUs 0-3,
      VCPUs 2-3 are pinned to CPUs 4-7,
      ...
      VCPUs 54-55 are pinned to CPUs 108-111

  guest B:
    - 4GB of memory
    - 4 VCPUs (sockets=1,cores=4,threads=1)

with the following workloads (with KSM and THP enabled in all):

  guest A:
    stress --cpu 40 --io 20 --vm 20 --vm-bytes 512M

  guest B:
    stress --cpu 4 --io 4 --vm 4 --vm-bytes 512M

  host:
    stress --cpu 4 --io 4 --vm 2 --vm-bytes 256M

the below soft-lockup traces were observed after an hour or so and
persisted until the host was reset (this was found to be reliably
reproducible for this configuration, for kernels 4.15, 4.18, 5.0,
and 5.3-rc5):

  [ 1253.183290] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1253.183319] rcu:     124-....: (5250 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=1941
  [ 1256.287426] watchdog: BUG: soft lockup - CPU#105 stuck for 23s! [CPU 52/KVM:19709]
  [ 1264.075773] watchdog: BUG: soft lockup - CPU#24 stuck for 23s! [worker:19913]
  [ 1264.079769] watchdog: BUG: soft lockup - CPU#31 stuck for 23s! [worker:20331]
  [ 1264.095770] watchdog: BUG: soft lockup - CPU#45 stuck for 23s! [worker:20338]
  [ 1264.131773] watchdog: BUG: soft lockup - CPU#64 stuck for 23s! [avocado:19525]
  [ 1280.408480] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1316.198012] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1316.198032] rcu:     124-....: (21003 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=8243
  [ 1340.411024] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1379.212609] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1379.212629] rcu:     124-....: (36756 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=14714
  [ 1404.413615] watchdog: BUG: soft lockup - CPU#124 stuck for 22s! [ksmd:791]
  [ 1442.227095] rcu: INFO: rcu_sched self-detected stall on CPU
  [ 1442.227115] rcu:     124-....: (52509 ticks this GP) idle=10a/1/0x4000000000000002 softirq=5408/5408 fqs=21403
  [ 1455.111787] INFO: task worker:19907 blocked for more than 120 seconds.
  [ 1455.111822]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111833] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.111884] INFO: task worker:19908 blocked for more than 120 seconds.
  [ 1455.111905]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111925] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.111966] INFO: task worker:20328 blocked for more than 120 seconds.
  [ 1455.111986]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.111998] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112048] INFO: task worker:20330 blocked for more than 120 seconds.
  [ 1455.112068]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112097] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112138] INFO: task worker:20332 blocked for more than 120 seconds.
  [ 1455.112159]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112179] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112210] INFO: task worker:20333 blocked for more than 120 seconds.
  [ 1455.112231]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112242] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112282] INFO: task worker:20335 blocked for more than 120 seconds.
  [ 1455.112303]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1
  [ 1455.112332] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
  [ 1455.112372] INFO: task worker:20336 blocked for more than 120 seconds.
  [ 1455.112392]       Tainted: G             L    5.3.0-rc5-mdr-vanilla+ #1

CPUs 45, 24, and 124 are stuck on spin locks, likely held by
CPUs 105 and 31.

CPUs 105 and 31 are stuck in smp_call_function_many(), waiting on
target CPU 42. For instance:

  # CPU 105 registers (via xmon)
  R00 = c00000000020b20c   R16 = 00007d1bcd800000
  R01 = c00000363eaa7970   R17 = 0000000000000001
  R02 = c0000000019b3a00   R18 = 000000000000006b
  R03 = 000000000000002a   R19 = 00007d537d7aecf0
  R04 = 000000000000002a   R20 = 60000000000000e0
  R05 = 000000000000002a   R21 = 0801000000000080
  R06 = c0002073fb0caa08   R22 = 0000000000000d60
  R07 = c0000000019ddd78   R23 = 0000000000000001
  R08 = 000000000000002a   R24 = c00000000147a700
  R09 = 0000000000000001   R25 = c0002073fb0ca908
  R10 = c000008ffeb4e660   R26 = 0000000000000000
  R11 = c0002073fb0ca900   R27 = c0000000019e2464
  R12 = c000000000050790   R28 = c0000000000812b0
  R13 = c000207fff623e00   R29 = c0002073fb0ca808
  R14 = 00007d1bbee00000   R30 = c0002073fb0ca800
  R15 = 00007d1bcd600000   R31 = 0000000000000800
  pc  = c00000000020b260 smp_call_function_many+0x3d0/0x460
  cfar= c00000000020b270 smp_call_function_many+0x3e0/0x460
  lr  = c00000000020b20c smp_call_function_many+0x37c/0x460
  msr = 900000010288b033   cr  = 44024824
  ctr = c000000000050790   xer = 0000000000000000   trap =  100

CPU 42 is running normally, doing VCPU work:

  # CPU 42 stack trace (via xmon)
  [link register   ] c00800001be17188 kvmppc_book3s_radix_page_fault+0x90/0x2b0 [kvm_hv]
  [c000008ed3343820] c000008ed3343850 (unreliable)
  [c000008ed33438d0] c00800001be11b6c kvmppc_book3s_hv_page_fault+0x264/0xe30 [kvm_hv]
  [c000008ed33439d0] c00800001be0d7b4 kvmppc_vcpu_run_hv+0x8dc/0xb50 [kvm_hv]
  [c000008ed3343ae0] c00800001c10891c kvmppc_vcpu_run+0x34/0x48 [kvm]
  [c000008ed3343b00] c00800001c10475c kvm_arch_vcpu_ioctl_run+0x244/0x420 [kvm]
  [c000008ed3343b90] c00800001c0f5a78 kvm_vcpu_ioctl+0x470/0x7c8 [kvm]
  [c000008ed3343d00] c000000000475450 do_vfs_ioctl+0xe0/0xc70
  [c000008ed3343db0] c0000000004760e4 ksys_ioctl+0x104/0x120
  [c000008ed3343e00] c000000000476128 sys_ioctl+0x28/0x80
  [c000008ed3343e20] c00000000000b388 system_call+0x5c/0x70
  --- Exception: c00 (System Call) at 00007d545cfd7694
  SP (7d53ff7edf50) is in userspace

It was subsequently found that ipi_message[PPC_MSG_CALL_FUNCTION]
was set for CPU 42 by at least 1 of the CPUs waiting in
smp_call_function_many(), but somehow the corresponding
call_single_queue entries were never processed by CPU 42, causing the
callers to spin in csd_lock_wait() indefinitely.

Nick Piggin suggested something similar to the following sequence as
a possible explanation (interleaving of CALL_FUNCTION/RESCHEDULE
IPI messages seems to be most common, but any mix of CALL_FUNCTION and
!CALL_FUNCTION messages could trigger it):

    CPU
      X: smp_muxed_ipi_set_message():
      X:   smp_mb()
      X:   message[RESCHEDULE] = 1
      X: doorbell_global_ipi(42):
      X:   kvmppc_set_host_ipi(42, 1)
      X:   ppc_msgsnd_sync()/smp_mb()
      X:   ppc_msgsnd() -> 42
     42: doorbell_exception(): // from CPU X
     42:   ppc_msgsync()
    105: smp_muxed_ipi_set_message():
    105:   smb_mb()
         // STORE DEFERRED DUE TO RE-ORDERING
  --105:   message[CALL_FUNCTION] = 1
  | 105: doorbell_global_ipi(42):
  | 105:   kvmppc_set_host_ipi(42, 1)
  |  42:   kvmppc_set_host_ipi(42, 0)
  |  42: smp_ipi_demux_relaxed()
  |  42: // returns to executing guest
  |      // RE-ORDERED STORE COMPLETES
  ->105:   message[CALL_FUNCTION] = 1
    105:   ppc_msgsnd_sync()/smp_mb()
    105:   ppc_msgsnd() -> 42
     42: local_paca->kvm_hstate.host_ipi == 0 // IPI ignored
    105: // hangs waiting on 42 to process messages/call_single_queue

This can be prevented with an smp_mb() at the beginning of
kvmppc_set_host_ipi(), such that stores to message[<type>] (or other
state indicated by the host_ipi flag) are ordered vs. the store to
to host_ipi.

However, doing so might still allow for the following scenario (not
yet observed):

    CPU
      X: smp_muxed_ipi_set_message():
      X:   smp_mb()
      X:   message[RESCHEDULE] = 1
      X: doorbell_global_ipi(42):
      X:   kvmppc_set_host_ipi(42, 1)
      X:   ppc_msgsnd_sync()/smp_mb()
      X:   ppc_msgsnd() -> 42
     42: doorbell_exception(): // from CPU X
     42:   ppc_msgsync()
         // STORE DEFERRED DUE TO RE-ORDERING
  -- 42:   kvmppc_set_host_ipi(42, 0)
  |  42: smp_ipi_demux_relaxed()
  | 105: smp_muxed_ipi_set_message():
  | 105:   smb_mb()
  | 105:   message[CALL_FUNCTION] = 1
  | 105: doorbell_global_ipi(42):
  | 105:   kvmppc_set_host_ipi(42, 1)
  |      // RE-ORDERED STORE COMPLETES
  -> 42:   kvmppc_set_host_ipi(42, 0)
     42: // returns to executing guest
    105:   ppc_msgsnd_sync()/smp_mb()
    105:   ppc_msgsnd() -> 42
     42: local_paca->kvm_hstate.host_ipi == 0 // IPI ignored
    105: // hangs waiting on 42 to process messages/call_single_queue

Fixing this scenario would require an smp_mb() *after* clearing
host_ipi flag in kvmppc_set_host_ipi() to order the store vs.
subsequent processing of IPI messages.

To handle both cases, this patch splits kvmppc_set_host_ipi() into
separate set/clear functions, where we execute smp_mb() prior to
setting host_ipi flag, and after clearing host_ipi flag. These
functions pair with each other to synchronize the sender and receiver
sides.

With that change in place the above workload ran for 20 hours without
triggering any lock-ups.

Fixes: 755563b ("powerpc/powernv: Fixes for hypervisor doorbell handling") # v4.0
Signed-off-by: Michael Roth <[email protected]>
Acked-by: Paul Mackerras <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Depending on the hardware and the hypervisor, the hcall H_BLOCK_REMOVE
may not be able to process all the page sizes for a segment base page
size, as reported by the TLB Invalidate Characteristics.

For each pair of base segment page size and actual page size, this
characteristic tells us the size of the block the hcall supports.

In the case, the hcall is not supporting a pair of base segment page
size, actual page size, it is returning H_PARAM which leads to a panic
like this:

  kernel BUG at /home/srikar/work/linux.git/arch/powerpc/platforms/pseries/lpar.c:466!
  Oops: Exception in kernel mode, sig: 5 [#1]
  BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 28 PID: 583 Comm: modprobe Not tainted 5.2.0-master #5
  NIP: c0000000000be8dc LR: c0000000000be880 CTR: 0000000000000000
  REGS: c0000007e77fb130 TRAP: 0700  Not tainted (5.2.0-master)
  MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI> CR: 42224824 XER: 20000000
  CFAR: c0000000000be8fc IRQMASK: 0
  GPR00: 0000000022224828 c0000007e77fb3c0 c000000001434d00 0000000000000005
  GPR04: 9000000004fa8c00 0000000000000000 0000000000000003 0000000000000001
  GPR08: c0000007e77fb450 0000000000000000 0000000000000001 ffffffffffffffff
  GPR12: c0000007e77fb450 c00000000edfcb80 0000cd7d3ea30000 c0000000016022b0
  GPR16: 00000000000000b0 0000cd7d3ea30000 0000000000000001 c080001f04f00105
  GPR20: 0000000000000003 0000000000000004 c000000fbeb05f58 c000000001602200
  GPR24: 0000000000000000 0000000000000004 8800000000000000 c000000000c5d148
  GPR28: c000000000000000 8000000000000000 a000000000000000 c0000007e77fb580
  NIP [c0000000000be8dc] .call_block_remove+0x12c/0x220
  LR [c0000000000be880] .call_block_remove+0xd0/0x220
  Call Trace:
    0xc000000fb8c00240 (unreliable)
    .pSeries_lpar_flush_hash_range+0x578/0x670
    .flush_hash_range+0x44/0x100
    .__flush_tlb_pending+0x3c/0xc0
    .zap_pte_range+0x7ec/0x830
    .unmap_page_range+0x3f4/0x540
    .unmap_vmas+0x94/0x120
    .exit_mmap+0xac/0x1f0
    .mmput+0x9c/0x1f0
    .do_exit+0x388/0xd60
    .do_group_exit+0x54/0x100
    .__se_sys_exit_group+0x14/0x20
    system_call+0x5c/0x70
  Instruction dump:
  39400001 38a00000 4800003c 60000000 60420000 7fa9e800 38e00000 419e0014
  7d29d278 7d290074 7929d182 69270001 <0b070000> 7d495378 394a0001 7fa93040

The call to H_BLOCK_REMOVE should only be made for the supported pair
of base segment page size, actual page size and using the correct
maximum block size.

Due to the required complexity in do_block_remove() and
call_block_remove(), and the fact that currently a block size of 8 is
returned by the hypervisor, we are only supporting 8 size block to the
H_BLOCK_REMOVE hcall.

In order to identify this limitation easily in the code, a local
define HBLKR_SUPPORTED_SIZE defining the currently supported block
size, and a dedicated checking helper is_supported_hlbkr() are
introduced.

For regular pages and hugetlb, the assumption is made that the page
size is equal to the base page size. For THP the page size is assumed
to be 16M.

Fixes: ba2dd8a ("powerpc/pseries/mm: call H_BLOCK_REMOVE")
Signed-off-by: Laurent Dufour <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
…c_in_kernel

Reported by syzkaller:

	kasan: GPF could be caused by NULL-ptr deref or user memory access
	general protection fault: 0000 [#1] PREEMPT SMP KASAN
	RIP: 0010:__apic_accept_irq+0x46/0x740 arch/x86/kvm/lapic.c:1029
	Call Trace:
	kvm_apic_set_irq+0xb4/0x140 arch/x86/kvm/lapic.c:558
	stimer_notify_direct arch/x86/kvm/hyperv.c:648 [inline]
	stimer_expiration arch/x86/kvm/hyperv.c:659 [inline]
	kvm_hv_process_stimers+0x594/0x1650 arch/x86/kvm/hyperv.c:686
	vcpu_enter_guest+0x2b2a/0x54b0 arch/x86/kvm/x86.c:7896
	vcpu_run+0x393/0xd40 arch/x86/kvm/x86.c:8152
	kvm_arch_vcpu_ioctl_run+0x636/0x900 arch/x86/kvm/x86.c:8360
	kvm_vcpu_ioctl+0x6cf/0xaf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2765

The testcase programs HV_X64_MSR_STIMERn_CONFIG/HV_X64_MSR_STIMERn_COUNT,
in addition, there is no lapic in the kernel, the counters value are small
enough in order that kvm_hv_process_stimers() inject this already-expired
timer interrupt into the guest through lapic in the kernel which triggers
the NULL deferencing. This patch fixes it by don't advertise direct mode
synthetic timers and discarding the inject when lapic is not in kernel.

syzkaller source: https://syzkaller.appspot.com/x/repro.c?x=1752fe0a600000

Reported-by: [email protected]
Cc: Paolo Bonzini <[email protected]>
Cc: Radim Krčmář <[email protected]>
Signed-off-by: Wanpeng Li <[email protected]>
Reviewed-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
With DEBUG_PAGEALLOC on, the following triggers.

  BUG: unable to handle page fault for address: ffff88859367c000
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 3001067 P4D 3001067 PUD 406d3a8067 PMD 406d30c067 PTE 800ffffa6c983060
  Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
  CPU: 38 PID: 3110657 Comm: python2.7
  RIP: 0010:fuse_readdir+0x88f/0xe7a [fuse]
  Code: 49 8b 4d 08 49 39 4e 60 0f 84 44 04 00 00 48 8b 43 08 43 8d 1c 3c 4d 01 7e 68 49 89 dc 48 03 5c 24 38 49 89 46 60 8b 44 24 30 <8b> 4b 10 44 29 e0 48 89 ca 48 83 c1 1f 48 83 e1 f8 83 f8 17 49 89
  RSP: 0018:ffffc90035edbde0 EFLAGS: 00010286
  RAX: 0000000000001000 RBX: ffff88859367bff0 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: ffff88859367bfed RDI: 0000000000920907
  RBP: ffffc90035edbe90 R08: 000000000000014b R09: 0000000000000004
  R10: ffff88859367b000 R11: 0000000000000000 R12: 0000000000000ff0
  R13: ffffc90035edbee0 R14: ffff889fb8546180 R15: 0000000000000020
  FS:  00007f80b5f4a740(0000) GS:ffff889fffa00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffff88859367c000 CR3: 0000001c170c2001 CR4: 00000000003606e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   iterate_dir+0x122/0x180
   __x64_sys_getdents+0xa6/0x140
   do_syscall_64+0x42/0x100
   entry_SYSCALL_64_after_hwframe+0x44/0xa9

It's in fuse_parse_cache().  %rbx (ffff88859367bff0) is fuse_dirent
pointer - addr + offset.  FUSE_DIRENT_SIZE() is trying to dereference
namelen off of it but that derefs into the next page which is disabled
by pagealloc debug causing a PF.

This is caused by dirent->namelen being accessed before ensuring that
there's enough bytes in the page for the dirent.  Fix it by pushing
down reclen calculation.

Signed-off-by: Tejun Heo <[email protected]>
Fixes: 5d7bc7e ("fuse: allow using readdir cache")
Cc: [email protected] # v4.20+
Signed-off-by: Miklos Szeredi <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
If the allocation done in tcf_exts_init() failed,
we end up with a NULL pointer in exts->actions.

kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 8198 Comm: syz-executor.3 Not tainted 5.3.0-rc8+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:tcf_action_destroy+0x71/0x160 net/sched/act_api.c:705
Code: c3 08 44 89 ee e8 4f cb bb fb 41 83 fd 20 0f 84 c9 00 00 00 e8 c0 c9 bb fb 48 89 d8 48 b9 00 00 00 00 00 fc ff df 48 c1 e8 03 <80> 3c 08 00 0f 85 c0 00 00 00 4c 8b 33 4d 85 f6 0f 84 9d 00 00 00
RSP: 0018:ffff888096e16ff0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
RDX: 0000000000040000 RSI: ffffffff85b6ab30 RDI: 0000000000000000
RBP: ffff888096e17020 R08: ffff8880993f6140 R09: fffffbfff11cae67
R10: fffffbfff11cae66 R11: ffffffff88e57333 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888096e177a0 R15: 0000000000000001
FS:  00007f62bc84a700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000758040 CR3: 0000000088b64000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 tcf_exts_destroy+0x38/0xb0 net/sched/cls_api.c:3030
 tcindex_set_parms+0xf7f/0x1e50 net/sched/cls_tcindex.c:488
 tcindex_change+0x230/0x318 net/sched/cls_tcindex.c:519
 tc_new_tfilter+0xa4b/0x1c70 net/sched/cls_api.c:2152
 rtnetlink_rcv_msg+0x838/0xb00 net/core/rtnetlink.c:5214
 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5241
 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline]
 netlink_unicast+0x531/0x710 net/netlink/af_netlink.c:1328
 netlink_sendmsg+0x8a5/0xd60 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]

Fixes: 90b73b7 ("net: sched: change action API to use array of pointers to actions")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Cc: Vlad Buslov <[email protected]>
Cc: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
With PFN_MODE_PMEM namespace, the memmap area is allocated from the device
area. Some architectures map the memmap area with large page size. On
architectures like ppc64, 16MB page for memap mapping can map 262144 pfns.
This maps a namespace size of 16G.

When populating memmap region with 16MB page from the device area,
make sure the allocated space is not used to map resources outside this
namespace. Such usage of device area will prevent a namespace destroy.

Add resource end pnf in altmap and use that to check if the memmap area
allocation can map pfn outside the namespace. On ppc64 in such case we fallback
to allocation from memory.

This fix kernel crash reported below:

[  132.034989] WARNING: CPU: 13 PID: 13719 at mm/memremap.c:133 devm_memremap_pages_release+0x2d8/0x2e0
[  133.464754] BUG: Unable to handle kernel data access at 0xc00c00010b204000
[  133.464760] Faulting instruction address: 0xc00000000007580c
[  133.464766] Oops: Kernel access of bad area, sig: 11 [#1]
[  133.464771] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
.....
[  133.464901] NIP [c00000000007580c] vmemmap_free+0x2ac/0x3d0
[  133.464906] LR [c0000000000757f8] vmemmap_free+0x298/0x3d0
[  133.464910] Call Trace:
[  133.464914] [c000007cbfd0f7b0] [c0000000000757f8] vmemmap_free+0x298/0x3d0 (unreliable)
[  133.464921] [c000007cbfd0f8d0] [c000000000370a44] section_deactivate+0x1a4/0x240
[  133.464928] [c000007cbfd0f980] [c000000000386270] __remove_pages+0x3a0/0x590
[  133.464935] [c000007cbfd0fa50] [c000000000074158] arch_remove_memory+0x88/0x160
[  133.464942] [c000007cbfd0fae0] [c0000000003be8c0] devm_memremap_pages_release+0x150/0x2e0
[  133.464949] [c000007cbfd0fb70] [c000000000738ea0] devm_action_release+0x30/0x50
[  133.464955] [c000007cbfd0fb90] [c00000000073a5a4] release_nodes+0x344/0x400
[  133.464961] [c000007cbfd0fc40] [c00000000073378c] device_release_driver_internal+0x15c/0x250
[  133.464968] [c000007cbfd0fc80] [c00000000072fd14] unbind_store+0x104/0x110
[  133.464973] [c000007cbfd0fcd0] [c00000000072ee24] drv_attr_store+0x44/0x70
[  133.464981] [c000007cbfd0fcf0] [c0000000004a32bc] sysfs_kf_write+0x6c/0xa0
[  133.464987] [c000007cbfd0fd10] [c0000000004a1dfc] kernfs_fop_write+0x17c/0x250
[  133.464993] [c000007cbfd0fd60] [c0000000003c348c] __vfs_write+0x3c/0x70
[  133.464999] [c000007cbfd0fd80] [c0000000003c75d0] vfs_write+0xd0/0x250

djbw: Aneesh notes that this crash can likely be triggered in any kernel that
supports 'papr_scm', so flagging that commit for -stable consideration.

Fixes: b5beae5 ("powerpc/pseries: Add driver for PAPR SCM regions")
Cc: <[email protected]>
Reported-by: Sachin Sant <[email protected]>
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Reviewed-by: Pankaj Gupta <[email protected]>
Tested-by: Santosh Sivaraj <[email protected]>
Reviewed-by: Johannes Thumshirn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Dan Williams <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Masoud Sharbiani noticed that commit 29ef680 ("memcg, oom: move
out_of_memory back to the charge path") broke memcg OOM called from
__xfs_filemap_fault() path.  It turned out that try_charge() is retrying
forever without making forward progress because mem_cgroup_oom(GFP_NOFS)
cannot invoke the OOM killer due to commit 3da88fb ("mm, oom:
move GFP_NOFS check to out_of_memory").

Allowing forced charge due to being unable to invoke memcg OOM killer will
lead to global OOM situation.  Also, just returning -ENOMEM will be risky
because OOM path is lost and some paths (e.g.  get_user_pages()) will leak
-ENOMEM.  Therefore, invoking memcg OOM killer (despite GFP_NOFS) will be
the only choice we can choose for now.

Until 29ef680, we were able to invoke memcg OOM killer when
GFP_KERNEL reclaim failed [1].  But since 29ef680, we need to
invoke memcg OOM killer when GFP_NOFS reclaim failed [2].  Although in the
past we did invoke memcg OOM killer for GFP_NOFS [3], we might get
pre-mature memcg OOM reports due to this patch.

[1]

 leaker invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), nodemask=(null), order=0, oom_score_adj=0
 CPU: 0 PID: 2746 Comm: leaker Not tainted 4.18.0+ #19
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  dump_stack+0x63/0x88
  dump_header+0x67/0x27a
  ? mem_cgroup_scan_tasks+0x91/0xf0
  oom_kill_process+0x210/0x410
  out_of_memory+0x10a/0x2c0
  mem_cgroup_out_of_memory+0x46/0x80
  mem_cgroup_oom_synchronize+0x2e4/0x310
  ? high_work_func+0x20/0x20
  pagefault_out_of_memory+0x31/0x76
  mm_fault_error+0x55/0x115
  ? handle_mm_fault+0xfd/0x220
  __do_page_fault+0x433/0x4e0
  do_page_fault+0x22/0x30
  ? page_fault+0x8/0x30
  page_fault+0x1e/0x30
 RIP: 0033:0x4009f0
 Code: 03 00 00 00 e8 71 fd ff ff 48 83 f8 ff 49 89 c6 74 74 48 89 c6 bf c0 0c 40 00 31 c0 e8 69 fd ff ff 45 85 ff 7e 21 31 c9 66 90 <41> 0f be 14 0e 01 d3 f7 c1 ff 0f 00 00 75 05 41 c6 04 0e 2a 48 83
 RSP: 002b:00007ffe29ae96f0 EFLAGS: 00010206
 RAX: 000000000000001b RBX: 0000000000000000 RCX: 0000000001ce1000
 RDX: 0000000000000000 RSI: 000000007fffffe5 RDI: 0000000000000000
 RBP: 000000000000000c R08: 0000000000000000 R09: 00007f94be09220d
 R10: 0000000000000002 R11: 0000000000000246 R12: 00000000000186a0
 R13: 0000000000000003 R14: 00007f949d845000 R15: 0000000002800000
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 158965
 memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 2016kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:844KB rss:521136KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:132KB writeback:0KB inactive_anon:0KB active_anon:521224KB inactive_file:1012KB active_file:8KB unevictable:0KB
 Memory cgroup out of memory: Kill process 2746 (leaker) score 998 or sacrifice child
 Killed process 2746 (leaker) total-vm:536704kB, anon-rss:521176kB, file-rss:1208kB, shmem-rss:0kB
 oom_reaper: reaped process 2746 (leaker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

[2]

 leaker invoked oom-killer: gfp_mask=0x600040(GFP_NOFS), nodemask=(null), order=0, oom_score_adj=0
 CPU: 1 PID: 2746 Comm: leaker Not tainted 4.18.0+ #20
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  dump_stack+0x63/0x88
  dump_header+0x67/0x27a
  ? mem_cgroup_scan_tasks+0x91/0xf0
  oom_kill_process+0x210/0x410
  out_of_memory+0x109/0x2d0
  mem_cgroup_out_of_memory+0x46/0x80
  try_charge+0x58d/0x650
  ? __radix_tree_replace+0x81/0x100
  mem_cgroup_try_charge+0x7a/0x100
  __add_to_page_cache_locked+0x92/0x180
  add_to_page_cache_lru+0x4d/0xf0
  iomap_readpages_actor+0xde/0x1b0
  ? iomap_zero_range_actor+0x1d0/0x1d0
  iomap_apply+0xaf/0x130
  iomap_readpages+0x9f/0x150
  ? iomap_zero_range_actor+0x1d0/0x1d0
  xfs_vm_readpages+0x18/0x20 [xfs]
  read_pages+0x60/0x140
  __do_page_cache_readahead+0x193/0x1b0
  ondemand_readahead+0x16d/0x2c0
  page_cache_async_readahead+0x9a/0xd0
  filemap_fault+0x403/0x620
  ? alloc_set_pte+0x12c/0x540
  ? _cond_resched+0x14/0x30
  __xfs_filemap_fault+0x66/0x180 [xfs]
  xfs_filemap_fault+0x27/0x30 [xfs]
  __do_fault+0x19/0x40
  __handle_mm_fault+0x8e8/0xb60
  handle_mm_fault+0xfd/0x220
  __do_page_fault+0x238/0x4e0
  do_page_fault+0x22/0x30
  ? page_fault+0x8/0x30
  page_fault+0x1e/0x30
 RIP: 0033:0x4009f0
 Code: 03 00 00 00 e8 71 fd ff ff 48 83 f8 ff 49 89 c6 74 74 48 89 c6 bf c0 0c 40 00 31 c0 e8 69 fd ff ff 45 85 ff 7e 21 31 c9 66 90 <41> 0f be 14 0e 01 d3 f7 c1 ff 0f 00 00 75 05 41 c6 04 0e 2a 48 83
 RSP: 002b:00007ffda45c9290 EFLAGS: 00010206
 RAX: 000000000000001b RBX: 0000000000000000 RCX: 0000000001a1e000
 RDX: 0000000000000000 RSI: 000000007fffffe5 RDI: 0000000000000000
 RBP: 000000000000000c R08: 0000000000000000 R09: 00007f6d061ff20d
 R10: 0000000000000002 R11: 0000000000000246 R12: 00000000000186a0
 R13: 0000000000000003 R14: 00007f6ce59b2000 R15: 0000000002800000
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 7221
 memory+swap: usage 0kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 1944kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:3632KB rss:518232KB rss_huge:0KB shmem:0KB mapped_file:0KB dirty:0KB writeback:0KB inactive_anon:0KB active_anon:518408KB inactive_file:3908KB active_file:12KB unevictable:0KB
 Memory cgroup out of memory: Kill process 2746 (leaker) score 992 or sacrifice child
 Killed process 2746 (leaker) total-vm:536704kB, anon-rss:518264kB, file-rss:1188kB, shmem-rss:0kB
 oom_reaper: reaped process 2746 (leaker), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

[3]

 leaker invoked oom-killer: gfp_mask=0x50, order=0, oom_score_adj=0
 leaker cpuset=/ mems_allowed=0
 CPU: 1 PID: 3206 Comm: leaker Not tainted 3.10.0-957.27.2.el7.x86_64 #1
 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/13/2018
 Call Trace:
  [<ffffffffaf364147>] dump_stack+0x19/0x1b
  [<ffffffffaf35eb6a>] dump_header+0x90/0x229
  [<ffffffffaedbb456>] ? find_lock_task_mm+0x56/0xc0
  [<ffffffffaee32a38>] ? try_get_mem_cgroup_from_mm+0x28/0x60
  [<ffffffffaedbb904>] oom_kill_process+0x254/0x3d0
  [<ffffffffaee36c36>] mem_cgroup_oom_synchronize+0x546/0x570
  [<ffffffffaee360b0>] ? mem_cgroup_charge_common+0xc0/0xc0
  [<ffffffffaedbc194>] pagefault_out_of_memory+0x14/0x90
  [<ffffffffaf35d072>] mm_fault_error+0x6a/0x157
  [<ffffffffaf3717c8>] __do_page_fault+0x3c8/0x4f0
  [<ffffffffaf371925>] do_page_fault+0x35/0x90
  [<ffffffffaf36d768>] page_fault+0x28/0x30
 Task in /leaker killed as a result of limit of /leaker
 memory: usage 524288kB, limit 524288kB, failcnt 20628
 memory+swap: usage 524288kB, limit 9007199254740988kB, failcnt 0
 kmem: usage 0kB, limit 9007199254740988kB, failcnt 0
 Memory cgroup stats for /leaker: cache:840KB rss:523448KB rss_huge:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:523448KB inactive_file:464KB active_file:376KB unevictable:0KB
 Memory cgroup out of memory: Kill process 3206 (leaker) score 970 or sacrifice child
 Killed process 3206 (leaker) total-vm:536692kB, anon-rss:523304kB, file-rss:412kB, shmem-rss:0kB

Bisected by Masoud Sharbiani.

Link: http://lkml.kernel.org/r/[email protected]
Fixes: 3da88fb ("mm, oom: move GFP_NOFS check to out_of_memory") [necessary after 29ef680]
Signed-off-by: Tetsuo Handa <[email protected]>
Reported-by: Masoud Sharbiani <[email protected]>
Tested-by: Masoud Sharbiani <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: <[email protected]>	[4.19+]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
An oops can be triggered in the scheduler when running qemu on arm64:

 Unable to handle kernel paging request at virtual address ffff000008effe40
 Internal error: Oops: 96000007 [#1] SMP
 Process migration/0 (pid: 12, stack limit = 0x00000000084e3736)
 pstate: 20000085 (nzCv daIf -PAN -UAO)
 pc : __ll_sc___cmpxchg_case_acq_4+0x4/0x20
 lr : move_queued_task.isra.21+0x124/0x298
 ...
 Call trace:
  __ll_sc___cmpxchg_case_acq_4+0x4/0x20
  __migrate_task+0xc8/0xe0
  migration_cpu_stop+0x170/0x180
  cpu_stopper_thread+0xec/0x178
  smpboot_thread_fn+0x1ac/0x1e8
  kthread+0x134/0x138
  ret_from_fork+0x10/0x18

__set_cpus_allowed_ptr() will choose an active dest_cpu in affinity mask to
migrage the process if process is not currently running on any one of the
CPUs specified in affinity mask. __set_cpus_allowed_ptr() will choose an
invalid dest_cpu (dest_cpu >= nr_cpu_ids, 1024 in my virtual machine) if
CPUS in an affinity mask are deactived by cpu_down after cpumask_intersects
check. cpumask_test_cpu() of dest_cpu afterwards is overflown and may pass if
corresponding bit is coincidentally set. As a consequence, kernel will
access an invalid rq address associate with the invalid CPU in
migration_cpu_stop->__migrate_task->move_queued_task and the Oops occurs.

The reproduce the crash:

  1) A process repeatedly binds itself to cpu0 and cpu1 in turn by calling
  sched_setaffinity.

  2) A shell script repeatedly does "echo 0 > /sys/devices/system/cpu/cpu1/online"
  and "echo 1 > /sys/devices/system/cpu/cpu1/online" in turn.

  3) Oops appears if the invalid CPU is set in memory after tested cpumask.

Signed-off-by: KeMeng Shi <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Valentin Schneider <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Thomas has noticed the following NULL ptr dereference when using cgroup
v1 kmem limit:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
PGD 0
P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 3 PID: 16923 Comm: gtk-update-icon Not tainted 4.19.51 #42
Hardware name: Gigabyte Technology Co., Ltd. Z97X-Gaming G1/Z97X-Gaming G1, BIOS F9 07/31/2015
RIP: 0010:create_empty_buffers+0x24/0x100
Code: cd 0f 1f 44 00 00 0f 1f 44 00 00 41 54 49 89 d4 ba 01 00 00 00 55 53 48 89 fb e8 97 fe ff ff 48 89 c5 48 89 c2 eb 03 48 89 ca <48> 8b 4a 08 4c 09 22 48 85 c9 75 f1 48 89 6a 08 48 8b 43 18 48 8d
RSP: 0018:ffff927ac1b37bf8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: fffff2d4429fd740 RCX: 0000000100097149
RDX: 0000000000000000 RSI: 0000000000000082 RDI: ffff9075a99fbe00
RBP: 0000000000000000 R08: fffff2d440949cc8 R09: 00000000000960c0
R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000
R13: ffff907601f18360 R14: 0000000000002000 R15: 0000000000001000
FS:  00007fb55b288bc0(0000) GS:ffff90761f8c0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000008 CR3: 000000007aebc002 CR4: 00000000001606e0
Call Trace:
 create_page_buffers+0x4d/0x60
 __block_write_begin_int+0x8e/0x5a0
 ? ext4_inode_attach_jinode.part.82+0xb0/0xb0
 ? jbd2__journal_start+0xd7/0x1f0
 ext4_da_write_begin+0x112/0x3d0
 generic_perform_write+0xf1/0x1b0
 ? file_update_time+0x70/0x140
 __generic_file_write_iter+0x141/0x1a0
 ext4_file_write_iter+0xef/0x3b0
 __vfs_write+0x17e/0x1e0
 vfs_write+0xa5/0x1a0
 ksys_write+0x57/0xd0
 do_syscall_64+0x55/0x160
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Tetsuo then noticed that this is because the __memcg_kmem_charge_memcg
fails __GFP_NOFAIL charge when the kmem limit is reached.  This is a wrong
behavior because nofail allocations are not allowed to fail.  Normal
charge path simply forces the charge even if that means to cross the
limit.  Kmem accounting should be doing the same.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Michal Hocko <[email protected]>
Reported-by: Thomas Lindroth <[email protected]>
Debugged-by: Tetsuo Handa <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Vladimir Davydov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Thomas Lindroth <[email protected]>
Cc: Shakeel Butt <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
I'm seeing a bunch of debug prints from a user of print_hex_dump_bytes()
in my kernel logs, but I don't have CONFIG_DYNAMIC_DEBUG enabled nor do I
have DEBUG defined in my build.  The problem is that
print_hex_dump_bytes() calls a wrapper function in lib/hexdump.c that
calls print_hex_dump() with KERN_DEBUG level.  There are three cases to
consider here

  1. CONFIG_DYNAMIC_DEBUG=y  --> call dynamic_hex_dum()
  2. CONFIG_DYNAMIC_DEBUG=n && DEBUG --> call print_hex_dump()
  3. CONFIG_DYNAMIC_DEBUG=n && !DEBUG --> stub it out

Right now, that last case isn't detected and we still call
print_hex_dump() from the stub wrapper.

Let's make print_hex_dump_bytes() only call print_hex_dump_debug() so that
it works properly in all cases.

Case #1, print_hex_dump_debug() calls dynamic_hex_dump() and we get same
behavior.  Case #2, print_hex_dump_debug() calls print_hex_dump() with
KERN_DEBUG and we get the same behavior.  Case #3, print_hex_dump_debug()
is a nop, changing behavior to what we want, i.e.  print nothing.

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Stephen Boyd <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
When removing a cbs instance when offloading is enabled, the crash
below can be observed.

The problem happens because that when offloading is enabled, the cbs
instance is not added to the list.

Also, the current code doesn't handle correctly the case when offload
is disabled without removing the qdisc: if the link speed changes the
credit calculations will be wrong. When we create the cbs instance
with offloading enabled, it's not added to the notification list, when
later we disable offloading, it's not in the list, so link speed
changes will not affect it.

The solution for both issues is the same, add the cbs instance being
created unconditionally to the global list, even if the link state
notification isn't useful "right now".

Crash log:

[518758.189866] BUG: kernel NULL pointer dereference, address: 0000000000000000
[518758.189870] #PF: supervisor read access in kernel mode
[518758.189871] #PF: error_code(0x0000) - not-present page
[518758.189872] PGD 0 P4D 0
[518758.189874] Oops: 0000 [#1] SMP PTI
[518758.189876] CPU: 3 PID: 4825 Comm: tc Not tainted 5.2.9 #1
[518758.189877] Hardware name: Gigabyte Technology Co., Ltd. Z390 AORUS ULTRA/Z390 AORUS ULTRA-CF, BIOS F7 03/14/2019
[518758.189881] RIP: 0010:__list_del_entry_valid+0x29/0xa0
[518758.189883] Code: 90 48 b8 00 01 00 00 00 00 ad de 55 48 8b 17 4c 8b 47 08 48 89 e5 48 39 c2 74 27 48 b8 00 02 00 00 00 00 ad de 49 39 c0 74 2d <49> 8b 30 48 39 fe 75 3d 48 8b 52 08 48 39 f2 75 4c b8 01 00 00 00
[518758.189885] RSP: 0018:ffffa27e43903990 EFLAGS: 00010207
[518758.189887] RAX: dead000000000200 RBX: ffff8bce69f0f000 RCX: 0000000000000000
[518758.189888] RDX: 0000000000000000 RSI: ffff8bce69f0f064 RDI: ffff8bce69f0f1e0
[518758.189890] RBP: ffffa27e43903990 R08: 0000000000000000 R09: ffff8bce69e788c0
[518758.189891] R10: ffff8bce62acd400 R11: 00000000000003cb R12: ffff8bce69e78000
[518758.189892] R13: ffff8bce69f0f140 R14: 0000000000000000 R15: 0000000000000000
[518758.189894] FS:  00007fa1572c8f80(0000) GS:ffff8bce6e0c0000(0000) knlGS:0000000000000000
[518758.189895] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[518758.189896] CR2: 0000000000000000 CR3: 000000040a398006 CR4: 00000000003606e0
[518758.189898] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[518758.189899] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[518758.189900] Call Trace:
[518758.189904]  cbs_destroy+0x32/0xa0 [sch_cbs]
[518758.189906]  qdisc_destroy+0x45/0x120
[518758.189907]  qdisc_put+0x25/0x30
[518758.189908]  qdisc_graft+0x2c1/0x450
[518758.189910]  tc_get_qdisc+0x1c8/0x310
[518758.189912]  ? get_page_from_freelist+0x91a/0xcb0
[518758.189914]  rtnetlink_rcv_msg+0x293/0x360
[518758.189916]  ? kmem_cache_alloc_node_trace+0x178/0x260
[518758.189918]  ? __kmalloc_node_track_caller+0x38/0x50
[518758.189920]  ? rtnl_calcit.isra.0+0xf0/0xf0
[518758.189922]  netlink_rcv_skb+0x48/0x110
[518758.189923]  rtnetlink_rcv+0x10/0x20
[518758.189925]  netlink_unicast+0x15b/0x1d0
[518758.189926]  netlink_sendmsg+0x1ea/0x380
[518758.189929]  sock_sendmsg+0x2f/0x40
[518758.189930]  ___sys_sendmsg+0x295/0x2f0
[518758.189932]  ? ___sys_recvmsg+0x151/0x1e0
[518758.189933]  ? do_wp_page+0x7e/0x450
[518758.189935]  __sys_sendmsg+0x48/0x80
[518758.189937]  __x64_sys_sendmsg+0x1a/0x20
[518758.189939]  do_syscall_64+0x53/0x1f0
[518758.189941]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[518758.189942] RIP: 0033:0x7fa15755169a
[518758.189944] Code: 48 c7 c0 ff ff ff ff eb be 0f 1f 80 00 00 00 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 18 b8 2e 00 00 00 c5 fc 77 0f 05 <48> 3d 00 f0 ff ff 77 5e c3 0f 1f 44 00 00 48 83 ec 28 89 54 24 1c
[518758.189946] RSP: 002b:00007ffda58b60b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[518758.189948] RAX: ffffffffffffffda RBX: 000055e4b836d9a0 RCX: 00007fa15755169a
[518758.189949] RDX: 0000000000000000 RSI: 00007ffda58b6128 RDI: 0000000000000003
[518758.189951] RBP: 00007ffda58b6190 R08: 0000000000000001 R09: 000055e4b9d848a0
[518758.189952] R10: 0000000000000000 R11: 0000000000000246 R12: 000000005d654b49
[518758.189953] R13: 0000000000000000 R14: 00007ffda58b6230 R15: 00007ffda58b6210
[518758.189955] Modules linked in: sch_cbs sch_etf sch_mqprio netlink_diag unix_diag e1000e igb intel_pch_thermal thermal video backlight pcc_cpufreq
[518758.189960] CR2: 0000000000000000
[518758.189961] ---[ end trace 6a13f7aaf5376019 ]---
[518758.189963] RIP: 0010:__list_del_entry_valid+0x29/0xa0
[518758.189964] Code: 90 48 b8 00 01 00 00 00 00 ad de 55 48 8b 17 4c 8b 47 08 48 89 e5 48 39 c2 74 27 48 b8 00 02 00 00 00 00 ad de 49 39 c0 74 2d <49> 8b 30 48 39 fe 75 3d 48 8b 52 08 48 39 f2 75 4c b8 01 00 00 00
[518758.189967] RSP: 0018:ffffa27e43903990 EFLAGS: 00010207
[518758.189968] RAX: dead000000000200 RBX: ffff8bce69f0f000 RCX: 0000000000000000
[518758.189969] RDX: 0000000000000000 RSI: ffff8bce69f0f064 RDI: ffff8bce69f0f1e0
[518758.189971] RBP: ffffa27e43903990 R08: 0000000000000000 R09: ffff8bce69e788c0
[518758.189972] R10: ffff8bce62acd400 R11: 00000000000003cb R12: ffff8bce69e78000
[518758.189973] R13: ffff8bce69f0f140 R14: 0000000000000000 R15: 0000000000000000
[518758.189975] FS:  00007fa1572c8f80(0000) GS:ffff8bce6e0c0000(0000) knlGS:0000000000000000
[518758.189976] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[518758.189977] CR2: 0000000000000000 CR3: 000000040a398006 CR4: 00000000003606e0
[518758.189979] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[518758.189980] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: e0a7683 ("net/sched: cbs: fix port_rate miscalculation")
Signed-off-by: Vinicius Costa Gomes <[email protected]>
Acked-by: Cong Wang <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
After commit a2c11b0 ("kcm: use BPF_PROG_RUN")
syzbot easily triggers the warning in cant_sleep().

As explained in commit 6cab5e9 ("bpf: run bpf programs
with preemption disabled") we need to disable preemption before
running bpf programs.

BUG: assuming atomic context at net/kcm/kcmsock.c:382
in_atomic(): 0, irqs_disabled(): 0, pid: 7, name: kworker/u4:0
3 locks held by kworker/u4:0/7:
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_data kernel/workqueue.c:620 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:647 [inline]
 #0: ffff888216726128 ((wq_completion)kstrp){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2240
 #1: ffff8880a989fdc0 ((work_completion)(&strp->work)){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2244
 #2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: lock_sock include/net/sock.h:1522 [inline]
 #2: ffff888098998d10 (sk_lock-AF_INET){+.+.}, at: strp_sock_lock+0x2e/0x40 net/strparser/strparser.c:440
CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: kstrp strp_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 __cant_sleep kernel/sched/core.c:6826 [inline]
 __cant_sleep.cold+0xa4/0xbc kernel/sched/core.c:6803
 kcm_parse_func_strparser+0x54/0x200 net/kcm/kcmsock.c:382
 __strp_recv+0x5dc/0x1b20 net/strparser/strparser.c:221
 strp_recv+0xcf/0x10b net/strparser/strparser.c:343
 tcp_read_sock+0x285/0xa00 net/ipv4/tcp.c:1639
 strp_read_sock+0x14d/0x200 net/strparser/strparser.c:366
 do_strp_work net/strparser/strparser.c:414 [inline]
 strp_work+0xe3/0x130 net/strparser/strparser.c:423
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269

Fixes: a2c11b0 ("kcm: use BPF_PROG_RUN")
Fixes: 6cab5e9 ("bpf: run bpf programs with preemption disabled")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
qdisc_root() use from netem_enqueue() triggers a lockdep warning.

__dev_queue_xmit() uses rcu_read_lock_bh() which is
not equivalent to rcu_read_lock() + local_bh_disable_bh as far
as lockdep is concerned.

WARNING: suspicious RCU usage
5.3.0-rc7+ #0 Not tainted
-----------------------------
include/net/sch_generic.h:492 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
3 locks held by syz-executor427/8855:
 #0: 00000000b5525c01 (rcu_read_lock_bh){....}, at: lwtunnel_xmit_redirect include/net/lwtunnel.h:92 [inline]
 #0: 00000000b5525c01 (rcu_read_lock_bh){....}, at: ip_finish_output2+0x2dc/0x2570 net/ipv4/ip_output.c:214
 #1: 00000000b5525c01 (rcu_read_lock_bh){....}, at: __dev_queue_xmit+0x20a/0x3650 net/core/dev.c:3804
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline]
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_xmit_skb net/core/dev.c:3502 [inline]
 #2: 00000000364bae92 (&(&sch->q.lock)->rlock){+.-.}, at: __dev_queue_xmit+0x14b8/0x3650 net/core/dev.c:3838

stack backtrace:
CPU: 0 PID: 8855 Comm: syz-executor427 Not tainted 5.3.0-rc7+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 lockdep_rcu_suspicious+0x153/0x15d kernel/locking/lockdep.c:5357
 qdisc_root include/net/sch_generic.h:492 [inline]
 netem_enqueue+0x1cfb/0x2d80 net/sched/sch_netem.c:479
 __dev_xmit_skb net/core/dev.c:3527 [inline]
 __dev_queue_xmit+0x15d2/0x3650 net/core/dev.c:3838
 dev_queue_xmit+0x18/0x20 net/core/dev.c:3902
 neigh_hh_output include/net/neighbour.h:500 [inline]
 neigh_output include/net/neighbour.h:509 [inline]
 ip_finish_output2+0x1726/0x2570 net/ipv4/ip_output.c:228
 __ip_finish_output net/ipv4/ip_output.c:308 [inline]
 __ip_finish_output+0x5fc/0xb90 net/ipv4/ip_output.c:290
 ip_finish_output+0x38/0x1f0 net/ipv4/ip_output.c:318
 NF_HOOK_COND include/linux/netfilter.h:294 [inline]
 ip_mc_output+0x292/0xf40 net/ipv4/ip_output.c:417
 dst_output include/net/dst.h:436 [inline]
 ip_local_out+0xbb/0x190 net/ipv4/ip_output.c:125
 ip_send_skb+0x42/0xf0 net/ipv4/ip_output.c:1555
 udp_send_skb.isra.0+0x6b2/0x1160 net/ipv4/udp.c:887
 udp_sendmsg+0x1e96/0x2820 net/ipv4/udp.c:1174
 inet_sendmsg+0x9e/0xe0 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg+0xd7/0x130 net/socket.c:657
 ___sys_sendmsg+0x3e2/0x920 net/socket.c:2311
 __sys_sendmmsg+0x1bf/0x4d0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg net/socket.c:2439 [inline]
 __x64_sys_sendmmsg+0x9d/0x100 net/socket.c:2439
 do_syscall_64+0xfd/0x6a0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: syzbot <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
We got a null pointer deference BUG_ON in blk_mq_rq_timed_out()
as following:

[  108.825472] BUG: kernel NULL pointer dereference, address: 0000000000000040
[  108.827059] PGD 0 P4D 0
[  108.827313] Oops: 0000 [#1] SMP PTI
[  108.827657] CPU: 6 PID: 198 Comm: kworker/6:1H Not tainted 5.3.0-rc8+ raspberrypi#431
[  108.829503] Workqueue: kblockd blk_mq_timeout_work
[  108.829913] RIP: 0010:blk_mq_check_expired+0x258/0x330
[  108.838191] Call Trace:
[  108.838406]  bt_iter+0x74/0x80
[  108.838665]  blk_mq_queue_tag_busy_iter+0x204/0x450
[  108.839074]  ? __switch_to_asm+0x34/0x70
[  108.839405]  ? blk_mq_stop_hw_queue+0x40/0x40
[  108.839823]  ? blk_mq_stop_hw_queue+0x40/0x40
[  108.840273]  ? syscall_return_via_sysret+0xf/0x7f
[  108.840732]  blk_mq_timeout_work+0x74/0x200
[  108.841151]  process_one_work+0x297/0x680
[  108.841550]  worker_thread+0x29c/0x6f0
[  108.841926]  ? rescuer_thread+0x580/0x580
[  108.842344]  kthread+0x16a/0x1a0
[  108.842666]  ? kthread_flush_work+0x170/0x170
[  108.843100]  ret_from_fork+0x35/0x40

The bug is caused by the race between timeout handle and completion for
flush request.

When timeout handle function blk_mq_rq_timed_out() try to read
'req->q->mq_ops', the 'req' have completed and reinitiated by next
flush request, which would call blk_rq_init() to clear 'req' as 0.

After commit 12f5b93 ("blk-mq: Remove generation seqeunce"),
normal requests lifetime are protected by refcount. Until 'rq->ref'
drop to zero, the request can really be free. Thus, these requests
cannot been reused before timeout handle finish.

However, flush request has defined .end_io and rq->end_io() is still
called even if 'rq->ref' doesn't drop to zero. After that, the 'flush_rq'
can be reused by the next flush request handle, resulting in null
pointer deference BUG ON.

We fix this problem by covering flush request with 'rq->ref'.
If the refcount is not zero, flush_end_io() return and wait the
last holder recall it. To record the request status, we add a new
entry 'rq_status', which will be used in flush_end_io().

Cc: Christoph Hellwig <[email protected]>
Cc: Keith Busch <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: [email protected] # v4.18+
Reviewed-by: Ming Lei <[email protected]>
Reviewed-by: Bob Liu <[email protected]>
Signed-off-by: Yufen Yu <[email protected]>

-------
v2:
 - move rq_status from struct request to struct blk_flush_queue
v3:
 - remove unnecessary '{}' pair.
v4:
 - let spinlock to protect 'fq->rq_status'
v5:
 - move rq_status after flush_running_idx member of struct blk_flush_queue
Signed-off-by: Jens Axboe <[email protected]>
lategoodbye pushed a commit that referenced this pull request Oct 10, 2019
Ido Schimmel says:

====================
mlxsw: Various fixes

This patchset includes two small fixes for the mlxsw driver and one
patch which clarifies recently introduced devlink-trap documentation.

Patch #1 clears the port's VLAN filters during port initialization. This
ensures that the drop reason reported to the user is consistent. The
problem is explained in detail in the commit message.

Patch #2 clarifies the description of one of the traps exposed via
devlink-trap.

Patch #3 from Danielle forbids the installation of a tc filter with
multiple mirror actions since this is not supported by the device. The
failure is communicated to the user via extack.
====================

Signed-off-by: David S. Miller <[email protected]>
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