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bnxt: don't enable NAPI until rings are ready
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[ Upstream commit 96ecdcc ]

Netpoll can try to poll napi as soon as napi_enable() is called.
It crashes trying to access a doorbell which is still NULL:

 BUG: kernel NULL pointer dereference, address: 0000000000000000
 CPU: 59 PID: 6039 Comm: ethtool Kdump: loaded Tainted: G S                5.9.0-rc1-00469-g5fd99b5d9950-dirty #26
 RIP: 0010:bnxt_poll+0x121/0x1c0
 Code: c4 20 44 89 e0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 41 8b 86 a0 01 00 00 41 23 85 18 01 00 00 49 8b 96 a8 01 00 00 0d 00 00 00 24 <89> 02
41 f6 45 77 02 74 cb 49 8b ae d8 01 00 00 31 c0 c7 44 24 1a
  netpoll_poll_dev+0xbd/0x1a0
  __netpoll_send_skb+0x1b2/0x210
  netpoll_send_udp+0x2c9/0x406
  write_ext_msg+0x1d7/0x1f0
  console_unlock+0x23c/0x520
  vprintk_emit+0xe0/0x1d0
  printk+0x58/0x6f
  x86_vector_activate.cold+0xf/0x46
  __irq_domain_activate_irq+0x50/0x80
  __irq_domain_activate_irq+0x32/0x80
  __irq_domain_activate_irq+0x32/0x80
  irq_domain_activate_irq+0x25/0x40
  __setup_irq+0x2d2/0x700
  request_threaded_irq+0xfb/0x160
  __bnxt_open_nic+0x3b1/0x750
  bnxt_open_nic+0x19/0x30
  ethtool_set_channels+0x1ac/0x220
  dev_ethtool+0x11ba/0x2240
  dev_ioctl+0x1cf/0x390
  sock_do_ioctl+0x95/0x130

Reported-by: Rob Sherwood <[email protected]>
Fixes: c0c050c ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Jakub Kicinski <[email protected]>
Reviewed-by: Michael Chan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
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kuba-moo authored and gregkh committed Sep 9, 2020
1 parent da7a167 commit f28f3cf
Showing 1 changed file with 4 additions and 8 deletions.
12 changes: 4 additions & 8 deletions drivers/net/ethernet/broadcom/bnxt/bnxt.c
Original file line number Diff line number Diff line change
Expand Up @@ -9132,15 +9132,15 @@ static int __bnxt_open_nic(struct bnxt *bp, bool irq_re_init, bool link_re_init)
}
}

bnxt_enable_napi(bp);
bnxt_debug_dev_init(bp);

rc = bnxt_init_nic(bp, irq_re_init);
if (rc) {
netdev_err(bp->dev, "bnxt_init_nic err: %x\n", rc);
goto open_err;
goto open_err_irq;
}

bnxt_enable_napi(bp);
bnxt_debug_dev_init(bp);

if (link_re_init) {
mutex_lock(&bp->link_lock);
rc = bnxt_update_phy_setting(bp);
Expand Down Expand Up @@ -9171,10 +9171,6 @@ static int __bnxt_open_nic(struct bnxt *bp, bool irq_re_init, bool link_re_init)
bnxt_vf_reps_open(bp);
return 0;

open_err:
bnxt_debug_dev_exit(bp);
bnxt_disable_napi(bp);

open_err_irq:
bnxt_del_napi(bp);

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