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iommu: Regulate EINVAL return values from ->attach_dev() #2

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These are a set of preparatory changes used by VFIO and IOMMUFD. It allows EINVAL to indicate an incompatibility between a domain and a device (or group).

They would have very minimal impact on the bare-metal host kernel since they only changed return values for error-out routines.

ianmay81 and others added 24 commits September 27, 2022 23:20
Ignore: yes
Signed-off-by: Ian May <[email protected]>
BugLink: https://bugs.launchpad.net/bugs/1991664

cbd/kteam-tools have been updated to install gcc-12 toolchain. dkms
dynamically checks and tries to use the same compiler version as the
kernel build. When backporting, the toolchain version should be set in
full to the versioned gcc-12, make it so. This is to support building
dkms modules with matching gcc in jammy.

Signed-off-by: Dimitri John Ledkov <[email protected]>
Signed-off-by: Andrea Righi <[email protected]>
(cherry picked from commit e96b739)
Ignore: yes
Signed-off-by: Dimitri John Ledkov <[email protected]>
BugLink: https://bugs.launchpad.net/bugs/1992162
Properties: no-test-build
Signed-off-by: Dimitri John Ledkov <[email protected]>
Ignore: yes
Signed-off-by: Ian May <[email protected]>
Cases like VFIO wish to attach a device to an existing domain that was
not allocated specifically from the device. This raises a condition
where the IOMMU driver can fail the domain attach because the domain and
device are incompatible with each other.

This is a soft failure that can be resolved by using a different domain.

Provide a dedicated errno EINVAL from the IOMMU driver during attach that
the reason why the attach failed is because of domain incompatibility.

VFIO can use this to know that the attach is a soft failure and it should
continue searching. Otherwise, the attach will be a hard failure and VFIO
will return the code to userspace.

Update kdocs to add rules of return value to the attach_dev op and APIs.

Link: https://lore.kernel.org/r/bd56d93c18621104a0fa1b0de31e9b760b81b769.1666042872.git.nicolinc@nvidia.com
Suggested-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
(cherry picked from commit 0020885)
Signed-off-by: Nicolin Chen <[email protected]>
Following the new rules in include/linux/iommu.h kdocs, EINVAL now can be
used to indicate that domain and device are incompatible by a caller that
treats it as a soft failure and tries attaching to another domain.

On the other hand, there are ->attach_dev callback functions returning it
for obvious device-specific errors. They will result in some inefficiency
in the caller handling routine.

Update these places to corresponding errnos following the new rules.

Link: https://lore.kernel.org/r/5924c03bea637f05feb2a20d624bae086b555ec5.1666042872.git.nicolinc@nvidia.com
Reviewed-by: Jean-Philippe Brucker <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
(cherry picked from commit bd7ebb7)
Signed-off-by: Nicolin Chen <[email protected]>
Following the new rules in include/linux/iommu.h kdocs, update all drivers
->attach_dev callback functions to return EINVAL in the failure paths that
are related to domain incompatibility.

Also, drop adjacent error prints to prevent a kernel log spam.

Link: https://lore.kernel.org/r/f52a07f7320da94afe575c9631340d0019a203a7.1666042873.git.nicolinc@nvidia.com
Reviewed-by: Jean-Philippe Brucker <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
(cherry picked from commit f4a1477)
Signed-off-by: Nicolin Chen <[email protected]>
The mtk_iommu and virtio drivers have places in the ->attach_dev callback
functions that return hardcode errnos instead of the returned values, but
callers of these ->attach_dv callback functions may care. Propagate them
directly without the extra conversions.

Link: https://lore.kernel.org/r/ca8c5a447b87002334f83325f28823008b4ce420.1666042873.git.nicolinc@nvidia.com
Reviewed-by: Kevin Tian <[email protected]>
Reviewed-by: Jean-Philippe Brucker <[email protected]>
Reviewed-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Yong Wu <[email protected]>
Signed-off-by: Nicolin Chen <[email protected]>
Signed-off-by: Jason Gunthorpe <[email protected]>
(cherry picked from commit 04cee82)
Signed-off-by: Nicolin Chen <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994061

commit 1016fc0 upstream.

A recent commit expanding the scope of the udc_lock mutex in the
gadget core managed to cause an obscure and slightly bizarre lockdep
violation.  In abbreviated form:

======================================================
WARNING: possible circular locking dependency detected
5.19.0-rc7+ #12510 Not tainted
------------------------------------------------------
udevadm/312 is trying to acquire lock:
ffff80000aae1058 (udc_lock){+.+.}-{3:3}, at: usb_udc_uevent+0x54/0xe0

but task is already holding lock:
ffff000002277548 (kn->active#4){++++}-{0:0}, at: kernfs_seq_start+0x34/0xe0

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (kn->active#4){++++}-{0:0}:
        lock_acquire+0x68/0x84
        __kernfs_remove+0x268/0x380
        kernfs_remove_by_name_ns+0x58/0xac
        sysfs_remove_file_ns+0x18/0x24
        device_del+0x15c/0x440

-> #2 (device_links_lock){+.+.}-{3:3}:
        lock_acquire+0x68/0x84
        __mutex_lock+0x9c/0x430
        mutex_lock_nested+0x38/0x64
        device_link_remove+0x3c/0xa0
        _regulator_put.part.0+0x168/0x190
        regulator_put+0x3c/0x54
        devm_regulator_release+0x14/0x20

-> #1 (regulator_list_mutex){+.+.}-{3:3}:
        lock_acquire+0x68/0x84
        __mutex_lock+0x9c/0x430
        mutex_lock_nested+0x38/0x64
        regulator_lock_dependent+0x54/0x284
        regulator_enable+0x34/0x80
        phy_power_on+0x24/0x130
        __dwc2_lowlevel_hw_enable+0x100/0x130
        dwc2_lowlevel_hw_enable+0x18/0x40
        dwc2_hsotg_udc_start+0x6c/0x2f0
        gadget_bind_driver+0x124/0x1f4

-> #0 (udc_lock){+.+.}-{3:3}:
        __lock_acquire+0x1298/0x20cc
        lock_acquire.part.0+0xe0/0x230
        lock_acquire+0x68/0x84
        __mutex_lock+0x9c/0x430
        mutex_lock_nested+0x38/0x64
        usb_udc_uevent+0x54/0xe0

Evidently this was caused by the scope of udc_mutex being too large.
The mutex is only meant to protect udc->driver along with a few other
things.  As far as I can tell, there's no reason for the mutex to be
held while the gadget core calls a gadget driver's ->bind or ->unbind
routine, or while a UDC is being started or stopped.  (This accounts
for link #1 in the chain above, where the mutex is held while the
dwc2_hsotg_udc is started as part of driver probing.)

Gadget drivers' ->disconnect callbacks are problematic.  Even though
usb_gadget_disconnect() will now acquire the udc_mutex, there's a
window in usb_gadget_bind_driver() between the times when the mutex is
released and the ->bind callback is invoked.  If a disconnect occurred
during that window, we could call the driver's ->disconnect routine
before its ->bind routine.  To prevent this from happening, it will be
necessary to prevent a UDC from connecting while it has no gadget
driver.  This should be done already but it doesn't seem to be;
currently usb_gadget_connect() has no check for this.  Such a check
will have to be added later.

Some degree of mutual exclusion is required in soft_connect_store(),
which can dereference udc->driver at arbitrary times since it is a
sysfs callback.  The solution here is to acquire the gadget's device
lock rather than the udc_mutex.  Since the driver core guarantees that
the device lock is always held during driver binding and unbinding,
this will make the accesses in soft_connect_store() mutually exclusive
with any changes to udc->driver.

Lastly, it turns out there is one place which should hold the
udc_mutex but currently does not: The function_show() routine needs
protection while it dereferences udc->driver.  The missing lock and
unlock calls are added.

Link: https://lore.kernel.org/all/[email protected]/
Fixes: 2191c00 ("USB: gadget: Fix use-after-free Read in usb_udc_uevent()")
Cc: Felipe Balbi <[email protected]>
Cc: [email protected]
Reported-by: Marek Szyprowski <[email protected]>
Tested-by: Marek Szyprowski <[email protected]>
Signed-off-by: Alan Stern <[email protected]>
Link: https://lore.kernel.org/r/YwkfhdxA/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994061

commit 902e02e upstream.

Syzkaller reports the following problem:

BUG: sleeping function called from invalid context at kernel/printk/printk.c:2347
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 1105, name: syz-executor423
3 locks held by syz-executor423/1105:
 #0: ffff8881468b9098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x90 drivers/tty/tty_ldisc.c:266
 #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:952 [inline]
 #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:975 [inline]
 #1: ffff8881468b9130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x2a8/0x8e0 drivers/tty/tty_io.c:1118
 #2: ffff88801b06c398 (&gsm->tx_lock){....}-{2:2}, at: gsmld_write+0x5e/0x150 drivers/tty/n_gsm.c:2717
irq event stamp: 3482
hardirqs last  enabled at (3481): [<ffffffff81d13343>] __get_reqs_available+0x143/0x2f0 fs/aio.c:946
hardirqs last disabled at (3482): [<ffffffff87d39722>] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]
hardirqs last disabled at (3482): [<ffffffff87d39722>] _raw_spin_lock_irqsave+0x52/0x60 kernel/locking/spinlock.c:159
softirqs last  enabled at (3408): [<ffffffff87e01002>] asm_call_irq_on_stack+0x12/0x20
softirqs last disabled at (3401): [<ffffffff87e01002>] asm_call_irq_on_stack+0x12/0x20
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 2 PID: 1105 Comm: syz-executor423 Not tainted 5.10.137-syzkaller #0
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x167 lib/dump_stack.c:118
 ___might_sleep.cold+0x1e8/0x22e kernel/sched/core.c:7304
 console_lock+0x19/0x80 kernel/printk/printk.c:2347
 do_con_write+0x113/0x1de0 drivers/tty/vt/vt.c:2909
 con_write+0x22/0xc0 drivers/tty/vt/vt.c:3296
 gsmld_write+0xd0/0x150 drivers/tty/n_gsm.c:2720
 do_tty_write drivers/tty/tty_io.c:1028 [inline]
 file_tty_write.constprop.0+0x502/0x8e0 drivers/tty/tty_io.c:1118
 call_write_iter include/linux/fs.h:1903 [inline]
 aio_write+0x355/0x7b0 fs/aio.c:1580
 __io_submit_one fs/aio.c:1952 [inline]
 io_submit_one+0xf45/0x1a90 fs/aio.c:1999
 __do_sys_io_submit fs/aio.c:2058 [inline]
 __se_sys_io_submit fs/aio.c:2028 [inline]
 __x64_sys_io_submit+0x18c/0x2f0 fs/aio.c:2028
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

The problem happens in the following control flow:

gsmld_write(...)
spin_lock_irqsave(&gsm->tx_lock, flags) // taken a spinlock on TX data
 con_write(...)
  do_con_write(...)
   console_lock()
    might_sleep() // -> bug

As far as console_lock() might sleep it should not be called with
spinlock held.

The patch replaces tx_lock spinlock with mutex in order to avoid the
problem.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 32dd59f ("tty: n_gsm: fix race condition in gsmld_write()")
Cc: stable <[email protected]>
Signed-off-by: Fedor Pchelkin <[email protected]>
Signed-off-by: Alexey Khoroshilov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994068

[ Upstream commit ac56a0b ]

Because rxrpc pretends to be a tunnel on top of a UDP/UDP6 socket, allowing
it to siphon off UDP packets early in the handling of received UDP packets
thereby avoiding the packet going through the UDP receive queue, it doesn't
get ICMP packets through the UDP ->sk_error_report() callback.  In fact, it
doesn't appear that there's any usable option for getting hold of ICMP
packets.

Fix this by adding a new UDP encap hook to distribute error messages for
UDP tunnels.  If the hook is set, then the tunnel driver will be able to
see ICMP packets.  The hook provides the offset into the packet of the UDP
header of the original packet that caused the notification.

An alternative would be to call the ->error_handler() hook - but that
requires that the skbuff be cloned (as ip_icmp_error() or ipv6_cmp_error()
do, though isn't really necessary or desirable in rxrpc's case is we want
to parse them there and then, not queue them).

Changes
=======
ver #3)
 - Fixed an uninitialised variable.

ver #2)
 - Fixed some missing CONFIG_AF_RXRPC_IPV6 conditionals.

Fixes: 5271953 ("rxrpc: Use the UDP encap_rcv hook")
Signed-off-by: David Howells <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994068

[ Upstream commit fb8396a ]

The driver incorrectly frees client instance and subsequent
i40e module removal leads to kernel crash.

Reproducer:
1. Do ethtool offline test followed immediately by another one
host# ethtool -t eth0 offline; ethtool -t eth0 offline
2. Remove recursively irdma module that also removes i40e module
host# modprobe -r irdma

Result:
[ 8675.035651] i40e 0000:3d:00.0 eno1: offline testing starting
[ 8675.193774] i40e 0000:3d:00.0 eno1: testing finished
[ 8675.201316] i40e 0000:3d:00.0 eno1: offline testing starting
[ 8675.358921] i40e 0000:3d:00.0 eno1: testing finished
[ 8675.496921] i40e 0000:3d:00.0: IRDMA hardware initialization FAILED init_state=2 status=-110
[ 8686.188955] i40e 0000:3d:00.1: i40e_ptp_stop: removed PHC on eno2
[ 8686.943890] i40e 0000:3d:00.1: Deleted LAN device PF1 bus=0x3d dev=0x00 func=0x01
[ 8686.952669] i40e 0000:3d:00.0: i40e_ptp_stop: removed PHC on eno1
[ 8687.761787] BUG: kernel NULL pointer dereference, address: 0000000000000030
[ 8687.768755] #PF: supervisor read access in kernel mode
[ 8687.773895] #PF: error_code(0x0000) - not-present page
[ 8687.779034] PGD 0 P4D 0
[ 8687.781575] Oops: 0000 [#1] PREEMPT SMP NOPTI
[ 8687.785935] CPU: 51 PID: 172891 Comm: rmmod Kdump: loaded Tainted: G        W I        5.19.0+ #2
[ 8687.794800] Hardware name: Intel Corporation S2600WFD/S2600WFD, BIOS SE5C620.86B.0X.02.0001.051420190324 05/14/2019
[ 8687.805222] RIP: 0010:i40e_lan_del_device+0x13/0xb0 [i40e]
[ 8687.810719] Code: d4 84 c0 0f 84 b8 25 01 00 e9 9c 25 01 00 41 bc f4 ff ff ff eb 91 90 0f 1f 44 00 00 41 54 55 53 48 8b 87 58 08 00 00 48 89 fb <48> 8b 68 30 48 89 ef e8 21 8a 0f d5 48 89 ef e8 a9 78 0f d5 48 8b
[ 8687.829462] RSP: 0018:ffffa604072efce0 EFLAGS: 00010202
[ 8687.834689] RAX: 0000000000000000 RBX: ffff8f43833b2000 RCX: 0000000000000000
[ 8687.841821] RDX: 0000000000000000 RSI: ffff8f4b0545b298 RDI: ffff8f43833b2000
[ 8687.848955] RBP: ffff8f43833b2000 R08: 0000000000000001 R09: 0000000000000000
[ 8687.856086] R10: 0000000000000000 R11: 000ffffffffff000 R12: ffff8f43833b2ef0
[ 8687.863218] R13: ffff8f43833b2ef0 R14: ffff915103966000 R15: ffff8f43833b2008
[ 8687.870342] FS:  00007f79501c3740(0000) GS:ffff8f4adffc0000(0000) knlGS:0000000000000000
[ 8687.878427] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8687.884174] CR2: 0000000000000030 CR3: 000000014276e004 CR4: 00000000007706e0
[ 8687.891306] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 8687.898441] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 8687.905572] PKRU: 55555554
[ 8687.908286] Call Trace:
[ 8687.910737]  <TASK>
[ 8687.912843]  i40e_remove+0x2c0/0x330 [i40e]
[ 8687.917040]  pci_device_remove+0x33/0xa0
[ 8687.920962]  device_release_driver_internal+0x1aa/0x230
[ 8687.926188]  driver_detach+0x44/0x90
[ 8687.929770]  bus_remove_driver+0x55/0xe0
[ 8687.933693]  pci_unregister_driver+0x2a/0xb0
[ 8687.937967]  i40e_exit_module+0xc/0xf48 [i40e]

Two offline tests cause IRDMA driver failure (ETIMEDOUT) and this
failure is indicated back to i40e_client_subtask() that calls
i40e_client_del_instance() to free client instance referenced
by pf->cinst and sets this pointer to NULL. During the module
removal i40e_remove() calls i40e_lan_del_device() that dereferences
pf->cinst that is NULL -> crash.
Do not remove client instance when client open callbacks fails and
just clear __I40E_CLIENT_INSTANCE_OPENED bit. The driver also needs
to take care about this situation (when netdev is up and client
is NOT opened) in i40e_notify_client_of_netdev_close() and
calls client close callback only when __I40E_CLIENT_INSTANCE_OPENED
is set.

Fixes: 0ef2d5a ("i40e: KISS the client interface")
Signed-off-by: Ivan Vecera <[email protected]>
Tested-by: Helena Anna Dubel <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994068

[ Upstream commit 84a5358 ]

The SRv6 layer allows defining HMAC data that can later be used to sign IPv6
Segment Routing Headers. This configuration is realised via netlink through
four attributes: SEG6_ATTR_HMACKEYID, SEG6_ATTR_SECRET, SEG6_ATTR_SECRETLEN and
SEG6_ATTR_ALGID. Because the SECRETLEN attribute is decoupled from the actual
length of the SECRET attribute, it is possible to provide invalid combinations
(e.g., secret = "", secretlen = 64). This case is not checked in the code and
with an appropriately crafted netlink message, an out-of-bounds read of up
to 64 bytes (max secret length) can occur past the skb end pointer and into
skb_shared_info:

Breakpoint 1, seg6_genl_sethmac (skb=<optimized out>, info=<optimized out>) at net/ipv6/seg6.c:208
208		memcpy(hinfo->secret, secret, slen);
(gdb) bt
 #0  seg6_genl_sethmac (skb=<optimized out>, info=<optimized out>) at net/ipv6/seg6.c:208
 #1  0xffffffff81e012e9 in genl_family_rcv_msg_doit (skb=skb@entry=0xffff88800b1f9f00, nlh=nlh@entry=0xffff88800b1b7600,
    extack=extack@entry=0xffffc90000ba7af0, ops=ops@entry=0xffffc90000ba7a80, hdrlen=4, net=0xffffffff84237580 <init_net>, family=<optimized out>,
    family=<optimized out>) at net/netlink/genetlink.c:731
 #2  0xffffffff81e01435 in genl_family_rcv_msg (extack=0xffffc90000ba7af0, nlh=0xffff88800b1b7600, skb=0xffff88800b1f9f00,
    family=0xffffffff82fef6c0 <seg6_genl_family>) at net/netlink/genetlink.c:775
 #3  genl_rcv_msg (skb=0xffff88800b1f9f00, nlh=0xffff88800b1b7600, extack=0xffffc90000ba7af0) at net/netlink/genetlink.c:792
 #4  0xffffffff81dfffc3 in netlink_rcv_skb (skb=skb@entry=0xffff88800b1f9f00, cb=cb@entry=0xffffffff81e01350 <genl_rcv_msg>)
    at net/netlink/af_netlink.c:2501
 #5  0xffffffff81e00919 in genl_rcv (skb=0xffff88800b1f9f00) at net/netlink/genetlink.c:803
 #6  0xffffffff81dff6ae in netlink_unicast_kernel (ssk=0xffff888010eec800, skb=0xffff88800b1f9f00, sk=0xffff888004aed000)
    at net/netlink/af_netlink.c:1319
 #7  netlink_unicast (ssk=ssk@entry=0xffff888010eec800, skb=skb@entry=0xffff88800b1f9f00, portid=portid@entry=0, nonblock=<optimized out>)
    at net/netlink/af_netlink.c:1345
 #8  0xffffffff81dff9a4 in netlink_sendmsg (sock=<optimized out>, msg=0xffffc90000ba7e48, len=<optimized out>) at net/netlink/af_netlink.c:1921
...
(gdb) p/x ((struct sk_buff *)0xffff88800b1f9f00)->head + ((struct sk_buff *)0xffff88800b1f9f00)->end
$1 = 0xffff88800b1b76c0
(gdb) p/x secret
$2 = 0xffff88800b1b76c0
(gdb) p slen
$3 = 64 '@'

The OOB data can then be read back from userspace by dumping HMAC state. This
commit fixes this by ensuring SECRETLEN cannot exceed the actual length of
SECRET.

Reported-by: Lucas Leong <[email protected]>
Tested: verified that EINVAL is correctly returned when secretlen > len(secret)
Fixes: 4f4853d ("ipv6: sr: implement API to control SR HMAC structure")
Signed-off-by: David Lebrun <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994070

[ Upstream commit 59bcdb5 ]

Using two different types of workoads, it was observed that
guc_update_engine_gt_clks was being called too frequently and/or
causing a CPU-to-lmem bandwidth hit over PCIE. Details on
the workloads and numbers are in the notes below.

Background: At the moment, guc_update_engine_gt_clks can be invoked
via one of 3 ways. #1 and #2 are infrequent under normal operating
conditions:
     1.When a predefined "ping_delay" timer expires so that GuC-
       busyness can sample the GTPM clock counter to ensure it
       doesn't miss a wrap-around of the 32-bits of the HW counter.
       (The ping_delay is calculated based on 1/8th the time taken
       for the counter go from 0x0 to 0xffffffff based on the
       GT frequency. This comes to about once every 28 seconds at a
       GT frequency of 19.2Mhz).
     2.In preparation for a gt reset.
     3.In response to __gt_park events (as the gt power management
       puts the gt into a lower power state when there is no work
       being done).

Root-cause: For both the workloads described farther below, it was
observed that when user space calls IOCTLs that unparks the
gt momentarily and repeats such calls many times in quick succession,
it triggers calling guc_update_engine_gt_clks as many times. However,
the primary purpose of guc_update_engine_gt_clks is to ensure we don't
miss the wraparound while the counter is ticking. Thus, the solution
is to ensure we skip that check if gt_park is calling this function
earlier than necessary.

Solution: Snapshot jiffies when we do actually update the busyness
stats. Then get the new jiffies every time intel_guc_busyness_park
is called and bail if we are being called too soon. Use half of the
ping_delay as a safe threshold.

NOTE1: Workload1: IGTs' gem_create was modified to create a file handle,
allocate memory with sizes that range from a min of 4K to the max supported
(in power of two step-sizes). Its maps, modifies and reads back the
memory. Allocations and modification is repeated until total memory
allocation reaches the max. Then the file handle is closed. With this
workload, guc_update_engine_gt_clks was called over 188 thousand times
in the span of 15 seconds while this test ran three times. With this patch,
the number of calls reduced to 14.

NOTE2: Workload2: 30 transcode sessions are created in quick succession.
While these sessions are created, pcm-iio tool was used to measure I/O
read operation bandwidth consumption sampled at 100 milisecond intervals
over the course of 20 seconds. The total bandwidth consumed over 20 seconds
without this patch was measured at average at 311KBps per sample. With this
patch, the number went down to about 175Kbps which is about a 43% savings.

Signed-off-by: Alan Previn <[email protected]>
Reviewed-by: Umesh Nerlige Ramappa <[email protected]>
Acked-by: Tvrtko Ursulin <[email protected]>
Signed-off-by: John Harrison <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
Stable-dep-of: aee5ae7 ("drm/i915/guc: Cancel GuC engine busyness worker synchronously")
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994074

[ Upstream commit 23c6191 ]

In the IDC callback that is accessed when the aux drivers request a reset,
the function to unplug the aux devices is called.  This function is also
called in the ice_prepare_for_reset function. This double call is causing
a "scheduling while atomic" BUG.

[  662.676430] ice 0000:4c:00.0 rocep76s0: cqp opcode = 0x1 maj_err_code = 0xffff min_err_code = 0x8003

[  662.676609] ice 0000:4c:00.0 rocep76s0: [Modify QP Cmd Error][op_code=8] status=-29 waiting=1 completion_err=1 maj=0xffff min=0x8003

[  662.815006] ice 0000:4c:00.0 rocep76s0: ICE OICR event notification: oicr = 0x10000003

[  662.815014] ice 0000:4c:00.0 rocep76s0: critical PE Error, GLPE_CRITERR=0x00011424

[  662.815017] ice 0000:4c:00.0 rocep76s0: Requesting a reset

[  662.815475] BUG: scheduling while atomic: swapper/37/0/0x00010002

[  662.815475] BUG: scheduling while atomic: swapper/37/0/0x00010002
[  662.815477] Modules linked in: rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs rfkill 8021q garp mrp stp llc vfat fat rpcrdma intel_rapl_msr intel_rapl_common sunrpc i10nm_edac rdma_ucm nfit ib_srpt libnvdimm ib_isert iscsi_target_mod x86_pkg_temp_thermal intel_powerclamp coretemp target_core_mod snd_hda_intel ib_iser snd_intel_dspcfg libiscsi snd_intel_sdw_acpi scsi_transport_iscsi kvm_intel iTCO_wdt rdma_cm snd_hda_codec kvm iw_cm ipmi_ssif iTCO_vendor_support snd_hda_core irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hwdep snd_seq snd_seq_device rapl snd_pcm snd_timer isst_if_mbox_pci pcspkr isst_if_mmio irdma intel_uncore idxd acpi_ipmi joydev isst_if_common snd mei_me idxd_bus ipmi_si soundcore i2c_i801 mei ipmi_devintf i2c_smbus i2c_ismt ipmi_msghandler acpi_power_meter acpi_pad rv(OE) ib_uverbs ib_cm ib_core xfs libcrc32c ast i2c_algo_bit drm_vram_helper drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm_ttm_helpe
 r ttm
[  662.815546]  nvme nvme_core ice drm crc32c_intel i40e t10_pi wmi pinctrl_emmitsburg dm_mirror dm_region_hash dm_log dm_mod fuse
[  662.815557] Preemption disabled at:
[  662.815558] [<0000000000000000>] 0x0
[  662.815563] CPU: 37 PID: 0 Comm: swapper/37 Kdump: loaded Tainted: G S         OE     5.17.1 #2
[  662.815566] Hardware name: Intel Corporation D50DNP/D50DNP, BIOS SE5C6301.86B.6624.D18.2111021741 11/02/2021
[  662.815568] Call Trace:
[  662.815572]  <IRQ>
[  662.815574]  dump_stack_lvl+0x33/0x42
[  662.815581]  __schedule_bug.cold.147+0x7d/0x8a
[  662.815588]  __schedule+0x798/0x990
[  662.815595]  schedule+0x44/0xc0
[  662.815597]  schedule_preempt_disabled+0x14/0x20
[  662.815600]  __mutex_lock.isra.11+0x46c/0x490
[  662.815603]  ? __ibdev_printk+0x76/0xc0 [ib_core]
[  662.815633]  device_del+0x37/0x3d0
[  662.815639]  ice_unplug_aux_dev+0x1a/0x40 [ice]
[  662.815674]  ice_schedule_reset+0x3c/0xd0 [ice]
[  662.815693]  irdma_iidc_event_handler.cold.7+0xb6/0xd3 [irdma]
[  662.815712]  ? bitmap_find_next_zero_area_off+0x45/0xa0
[  662.815719]  ice_send_event_to_aux+0x54/0x70 [ice]
[  662.815741]  ice_misc_intr+0x21d/0x2d0 [ice]
[  662.815756]  __handle_irq_event_percpu+0x4c/0x180
[  662.815762]  handle_irq_event_percpu+0xf/0x40
[  662.815764]  handle_irq_event+0x34/0x60
[  662.815766]  handle_edge_irq+0x9a/0x1c0
[  662.815770]  __common_interrupt+0x62/0x100
[  662.815774]  common_interrupt+0xb4/0xd0
[  662.815779]  </IRQ>
[  662.815780]  <TASK>
[  662.815780]  asm_common_interrupt+0x1e/0x40
[  662.815785] RIP: 0010:cpuidle_enter_state+0xd6/0x380
[  662.815789] Code: 49 89 c4 0f 1f 44 00 00 31 ff e8 65 d7 95 ff 45 84 ff 74 12 9c 58 f6 c4 02 0f 85 64 02 00 00 31 ff e8 ae c5 9c ff fb 45 85 f6 <0f> 88 12 01 00 00 49 63 d6 4c 2b 24 24 48 8d 04 52 48 8d 04 82 49
[  662.815791] RSP: 0018:ff2c2c4f18edbe80 EFLAGS: 00000202
[  662.815793] RAX: ff280805df140000 RBX: 0000000000000002 RCX: 000000000000001f
[  662.815795] RDX: 0000009a52da2d08 RSI: ffffffff93f8240b RDI: ffffffff93f53ee7
[  662.815796] RBP: ff5e2bd11ff41928 R08: 0000000000000000 R09: 000000000002f8c0
[  662.815797] R10: 0000010c3f18e2cf R11: 000000000000000f R12: 0000009a52da2d08
[  662.815798] R13: ffffffff94ad7e20 R14: 0000000000000002 R15: 0000000000000000
[  662.815801]  cpuidle_enter+0x29/0x40
[  662.815803]  do_idle+0x261/0x2b0
[  662.815807]  cpu_startup_entry+0x19/0x20
[  662.815809]  start_secondary+0x114/0x150
[  662.815813]  secondary_startup_64_no_verify+0xd5/0xdb
[  662.815818]  </TASK>
[  662.815846] bad: scheduling from the idle thread!
[  662.815849] CPU: 37 PID: 0 Comm: swapper/37 Kdump: loaded Tainted: G S      W  OE     5.17.1 #2
[  662.815852] Hardware name: Intel Corporation D50DNP/D50DNP, BIOS SE5C6301.86B.6624.D18.2111021741 11/02/2021
[  662.815853] Call Trace:
[  662.815855]  <IRQ>
[  662.815856]  dump_stack_lvl+0x33/0x42
[  662.815860]  dequeue_task_idle+0x20/0x30
[  662.815863]  __schedule+0x1c3/0x990
[  662.815868]  schedule+0x44/0xc0
[  662.815871]  schedule_preempt_disabled+0x14/0x20
[  662.815873]  __mutex_lock.isra.11+0x3a8/0x490
[  662.815876]  ? __ibdev_printk+0x76/0xc0 [ib_core]
[  662.815904]  device_del+0x37/0x3d0
[  662.815909]  ice_unplug_aux_dev+0x1a/0x40 [ice]
[  662.815937]  ice_schedule_reset+0x3c/0xd0 [ice]
[  662.815961]  irdma_iidc_event_handler.cold.7+0xb6/0xd3 [irdma]
[  662.815979]  ? bitmap_find_next_zero_area_off+0x45/0xa0
[  662.815985]  ice_send_event_to_aux+0x54/0x70 [ice]
[  662.816011]  ice_misc_intr+0x21d/0x2d0 [ice]
[  662.816033]  __handle_irq_event_percpu+0x4c/0x180
[  662.816037]  handle_irq_event_percpu+0xf/0x40
[  662.816039]  handle_irq_event+0x34/0x60
[  662.816042]  handle_edge_irq+0x9a/0x1c0
[  662.816045]  __common_interrupt+0x62/0x100
[  662.816048]  common_interrupt+0xb4/0xd0
[  662.816052]  </IRQ>
[  662.816053]  <TASK>
[  662.816054]  asm_common_interrupt+0x1e/0x40
[  662.816057] RIP: 0010:cpuidle_enter_state+0xd6/0x380
[  662.816060] Code: 49 89 c4 0f 1f 44 00 00 31 ff e8 65 d7 95 ff 45 84 ff 74 12 9c 58 f6 c4 02 0f 85 64 02 00 00 31 ff e8 ae c5 9c ff fb 45 85 f6 <0f> 88 12 01 00 00 49 63 d6 4c 2b 24 24 48 8d 04 52 48 8d 04 82 49
[  662.816063] RSP: 0018:ff2c2c4f18edbe80 EFLAGS: 00000202
[  662.816065] RAX: ff280805df140000 RBX: 0000000000000002 RCX: 000000000000001f
[  662.816067] RDX: 0000009a52da2d08 RSI: ffffffff93f8240b RDI: ffffffff93f53ee7
[  662.816068] RBP: ff5e2bd11ff41928 R08: 0000000000000000 R09: 000000000002f8c0
[  662.816070] R10: 0000010c3f18e2cf R11: 000000000000000f R12: 0000009a52da2d08
[  662.816071] R13: ffffffff94ad7e20 R14: 0000000000000002 R15: 0000000000000000
[  662.816075]  cpuidle_enter+0x29/0x40
[  662.816077]  do_idle+0x261/0x2b0
[  662.816080]  cpu_startup_entry+0x19/0x20
[  662.816083]  start_secondary+0x114/0x150
[  662.816087]  secondary_startup_64_no_verify+0xd5/0xdb
[  662.816091]  </TASK>
[  662.816169] bad: scheduling from the idle thread!

The correct place to unplug the aux devices for a reset is in the
prepare_for_reset function, as this is a common place for all reset flows.
It also has built in protection from being called twice in a single reset
instance before the aux devices are replugged.

Fixes: f9f5301 ("ice: Register auxiliary device to provide RDMA")
Signed-off-by: Dave Ertman <[email protected]>
Tested-by: Helena Anna Dubel <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994179

[ Upstream commit 2cbb958 ]

When we get a DMA channel and try to use it in multiple threads it
will cause oops and hanging the system.

% echo 100 > /sys/module/dmatest/parameters/threads_per_chan
% echo 100 > /sys/module/dmatest/parameters/iterations
% echo 1 > /sys/module/dmatest/parameters/run
[383493.327077] Unable to handle kernel paging request at virtual
		address dead000000000108
[383493.335103] Mem abort info:
[383493.335103]   ESR = 0x96000044
[383493.335105]   EC = 0x25: DABT (current EL), IL = 32 bits
[383493.335107]   SET = 0, FnV = 0
[383493.335108]   EA = 0, S1PTW = 0
[383493.335109]   FSC = 0x04: level 0 translation fault
[383493.335110] Data abort info:
[383493.335111]   ISV = 0, ISS = 0x00000044
[383493.364739]   CM = 0, WnR = 1
[383493.367793] [dead000000000108] address between user and kernel
		address ranges
[383493.375021] Internal error: Oops: 96000044 [#1] PREEMPT SMP
[383493.437574] CPU: 63 PID: 27895 Comm: dma0chan0-copy2 Kdump:
		loaded Tainted: GO 5.17.0-rc4+ #2
[383493.457851] pstate: 204000c9 (nzCv daIF +PAN -UAO -TCO -DIT
		-SSBS BTYPE=--)
[383493.465331] pc : vchan_tx_submit+0x64/0xa0
[383493.469957] lr : vchan_tx_submit+0x34/0xa0

This occurs because the transmission timed out, and that's due
to data race. Each thread rewrite channels's descriptor as soon as
device_issue_pending is called. It leads to the situation that
the driver thinks that it uses the right descriptor in interrupt
handler while channels's descriptor has been changed by other
thread. The descriptor which in fact reported interrupt will not
be handled any more, as well as its tx->callback.
That's why timeout reports.

With current fixes channels' descriptor changes it's value only
when it has been used. A new descriptor is acquired from
vc->desc_issued queue that is already filled with descriptors
that are ready to be sent. Threads have no direct access to DMA
channel descriptor. In case of channel's descriptor is busy, try
to submit to HW again when a descriptor is completed. In this case,
vc->desc_issued may be empty when hisi_dma_start_transfer is called,
so delete error reporting on this. Now it is just possible to queue
a descriptor for further processing.

Fixes: e9f08b6 ("dmaengine: hisilicon: Add Kunpeng DMA engine support")
Signed-off-by: Jie Hai <[email protected]>
Acked-by: Zhou Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Vinod Koul <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 19, 2023
BugLink: https://bugs.launchpad.net/bugs/1994179

[ Upstream commit 99ee931 ]

There is a recursive lock on the cpu_hotplug_lock.

In kernel/trace/trace_osnoise.c:<start/stop>_per_cpu_kthreads:
    - start_per_cpu_kthreads calls cpus_read_lock() and if
	start_kthreads returns a error it will call stop_per_cpu_kthreads.
    - stop_per_cpu_kthreads then calls cpus_read_lock() again causing
      deadlock.

Fix this by calling cpus_read_unlock() before calling
stop_per_cpu_kthreads. This behavior can also be seen in commit
f46b165 ("trace/hwlat: Implement the per-cpu mode").

This error was noticed during the LTP ftrace-stress-test:

WARNING: possible recursive locking detected
--------------------------------------------
sh/275006 is trying to acquire lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: stop_per_cpu_kthreads

but task is already holding lock:
ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads

other info that might help us debug this:
 Possible unsafe locking scenario:

      CPU0
      ----
 lock(cpu_hotplug_lock);
 lock(cpu_hotplug_lock);

 *** DEADLOCK ***

May be due to missing lock nesting notation

3 locks held by sh/275006:
 #0: ffff8881023f0470 (sb_writers#24){.+.+}-{0:0}, at: ksys_write
 #1: ffffffffb084f430 (trace_types_lock){+.+.}-{3:3}, at: rb_simple_write
 #2: ffffffffb02f5400 (cpu_hotplug_lock){++++}-{0:0}, at: start_per_cpu_kthreads

Link: https://lkml.kernel.org/r/[email protected]

Fixes: c8895e2 ("trace/osnoise: Support hotplug operations")
Signed-off-by: Nico Pache <[email protected]>
Acked-by: Daniel Bristot de Oliveira <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 22, 2023
BugLink: https://bugs.launchpad.net/bugs/1996540

[ Upstream commit 2bc9cd6 ]

If an IIO driver uses callbacks from another IIO driver and calls
iio_channel_start_all_cb() from one of its buffer setup ops, then
lockdep complains due to the lock nesting, as in the below example with
lmp91000.

Since the locks are being taken on different IIO devices, there is no
actual deadlock.  Fix the warning by telling lockdep to use a different
class for each iio_device.

 ============================================
 WARNING: possible recursive locking detected
 --------------------------------------------
 python3/23 is trying to acquire lock:
 (&indio_dev->mlock){+.+.}-{3:3}, at: iio_update_buffers

 but task is already holding lock:
 (&indio_dev->mlock){+.+.}-{3:3}, at: enable_store

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&indio_dev->mlock);
   lock(&indio_dev->mlock);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 5 locks held by python3/23:
  #0: (sb_writers#5){.+.+}-{0:0}, at: ksys_write
  #1: (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter
  #2: (kn->active#14){.+.+}-{0:0}, at: kernfs_fop_write_iter
  #3: (&indio_dev->mlock){+.+.}-{3:3}, at: enable_store
  #4: (&iio_dev_opaque->info_exist_lock){+.+.}-{3:3}, at: iio_update_buffers

 Call Trace:
  __mutex_lock
  iio_update_buffers
  iio_channel_start_all_cb
  lmp91000_buffer_postenable
  __iio_update_buffers
  enable_store

Fixes: 67e1730 ("iio: potentiostat: add LMP91000 support")
Signed-off-by: Vincent Whitchurch <[email protected]>
Reviewed-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jonathan Cameron <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
Signed-off-by: Stefan Bader <[email protected]>
nvidia-bfigg pushed a commit that referenced this pull request Jan 22, 2023
BugLink: https://bugs.launchpad.net/bugs/1999828

commit 024f4b2 upstream.

The cortex_a76_erratum_1463225_debug_handler() function is called when
handling debug exceptions (and synchronous exceptions from BRK
instructions), and so is called when a probed function executes. If the
compiler does not inline cortex_a76_erratum_1463225_debug_handler(), it
can be probed.

If cortex_a76_erratum_1463225_debug_handler() is probed, any debug
exception or software breakpoint exception will result in recursive
exceptions leading to a stack overflow. This can be triggered with the
ftrace multiple_probes selftest, and as per the example splat below.

This is a regression caused by commit:

  6459b84 ("arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround")

... which removed the NOKPROBE_SYMBOL() annotation associated with the
function.

My intent was that cortex_a76_erratum_1463225_debug_handler() would be
inlined into its caller, el1_dbg(), which is marked noinstr and cannot
be probed. Mark cortex_a76_erratum_1463225_debug_handler() as
__always_inline to ensure this.

Example splat prior to this patch (with recursive entries elided):

| # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events
| # echo p do_el0_svc >> /sys/kernel/debug/tracing/kprobe_events
| # echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable
| Insufficient stack space to handle exception!
| ESR: 0x0000000096000047 -- DABT (current EL)
| FAR: 0xffff800009cefff0
| Task stack:     [0xffff800009cf0000..0xffff800009cf4000]
| IRQ stack:      [0xffff800008000000..0xffff800008004000]
| Overflow stack: [0xffff00007fbc00f0..0xffff00007fbc10f0]
| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2
| Hardware name: linux,dummy-virt (DT)
| pstate: 604003c5 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : arm64_enter_el1_dbg+0x4/0x20
| lr : el1_dbg+0x24/0x5c
| sp : ffff800009cf0000
| x29: ffff800009cf0000 x28: ffff000002c74740 x27: 0000000000000000
| x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000
| x23: 00000000604003c5 x22: ffff80000801745c x21: 0000aaaac95ac068
| x20: 00000000f2000004 x19: ffff800009cf0040 x18: 0000000000000000
| x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
| x11: 0000000000000010 x10: ffff800008c87190 x9 : ffff800008ca00d0
| x8 : 000000000000003c x7 : 0000000000000000 x6 : 0000000000000000
| x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000000043a4
| x2 : 00000000f2000004 x1 : 00000000f2000004 x0 : ffff800009cf0040
| Kernel panic - not syncing: kernel stack overflow
| CPU: 0 PID: 145 Comm: sh Not tainted 6.0.0 #2
| Hardware name: linux,dummy-virt (DT)
| Call trace:
|  dump_backtrace+0xe4/0x104
|  show_stack+0x18/0x4c
|  dump_stack_lvl+0x64/0x7c
|  dump_stack+0x18/0x38
|  panic+0x14c/0x338
|  test_taint+0x0/0x2c
|  panic_bad_stack+0x104/0x118
|  handle_bad_stack+0x34/0x48
|  __bad_stack+0x78/0x7c
|  arm64_enter_el1_dbg+0x4/0x20
|  el1h_64_sync_handler+0x40/0x98
|  el1h_64_sync+0x64/0x68
|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34
...
|  el1h_64_sync_handler+0x40/0x98
|  el1h_64_sync+0x64/0x68
|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34
...
|  el1h_64_sync_handler+0x40/0x98
|  el1h_64_sync+0x64/0x68
|  cortex_a76_erratum_1463225_debug_handler+0x0/0x34
|  el1h_64_sync_handler+0x40/0x98
|  el1h_64_sync+0x64/0x68
|  do_el0_svc+0x0/0x28
|  el0t_64_sync_handler+0x84/0xf0
|  el0t_64_sync+0x18c/0x190
| Kernel Offset: disabled
| CPU features: 0x0080,00005021,19001080
| Memory Limit: none
| ---[ end Kernel panic - not syncing: kernel stack overflow ]---

With this patch, cortex_a76_erratum_1463225_debug_handler() is inlined
into el1_dbg(), and el1_dbg() cannot be probed:

| # echo p cortex_a76_erratum_1463225_debug_handler > /sys/kernel/debug/tracing/kprobe_events
| sh: write error: No such file or directory
| # grep -w cortex_a76_erratum_1463225_debug_handler /proc/kallsyms | wc -l
| 0
| # echo p el1_dbg > /sys/kernel/debug/tracing/kprobe_events
| sh: write error: Invalid argument
| # grep -w el1_dbg /proc/kallsyms | wc -l
| 1

Fixes: 6459b84 ("arm64: entry: consolidate Cortex-A76 erratum 1463225 workaround")
Cc: <[email protected]> # 5.12.x
Signed-off-by: Mark Rutland <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Kamal Mostafa <[email protected]>
Signed-off-by: Luke Nowakowski-Krijger <[email protected]>
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4 participants