This bug is awaiting verification that the kernel in -proposed solves
the problem. Please test the kernel and update this bug with the
results. If the problem is solved, change the tag 'verification-needed-
xenial' to 'verification-done-xenial'. If the problem still exists,
change the tag 'verification-needed-xenial' to 'verification-failed-

If verification is not done by 5 working days from today, this fix will
be dropped from the source code, and this bug will be closed.

See for documentation how
to enable and use -proposed. Thank you!

** Tags added: verification-needed-xenial

** Tags added: verification-needed-yakkety

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  [Hyper-V][Mellanox] net/mlx4_core: Avoid delays during VF driver
  device shutdown

Status in linux package in Ubuntu:
  Fix Released
Status in linux source package in Xenial:
  Fix Committed
Status in linux source package in Yakkety:
  In Progress
Status in linux source package in Zesty:
  Fix Released

Bug description:
  Mellanox has submitted the following patch upstream that's important
  for SR-IOV in Azure.

  Please integrate it into the Mellanox mlx4 drivers for lts-xenial,
  HWE, Zesty, and Azure custom.

  From: Jack Morgenstein <>

  Some Hypervisors detach VFs from VMs by instantly causing an FLR event
  to be generated for a VF.

  In the mlx4 case, this will cause that VF's comm channel to be disabled
  before the VM has an opportunity to invoke the VF device's "shutdown"

  For such Hypervisors, there is a race condition between the VF's
  shutdown method and its internal-error detection/reset thread.

  The internal-error detection/reset thread (which runs every 5 seconds) also
  detects a disabled comm channel. If the internal-error detection/reset
  flow wins the race, we still get delays (while that flow tries repeatedly
  to detect comm-channel recovery).

  The cited commit fixed the command timeout problem when the
  internal-error detection/reset flow loses the race.

  This commit avoids the unneeded delays when the internal-error
  detection/reset flow wins.

  Fixes: d585df1c5ccf ("net/mlx4_core: Avoid command timeouts during VF driver 
device shutdown")
  Signed-off-by: Jack Morgenstein <>
  Reported-by: Simon Xiao <>
  Signed-off-by: Tariq Toukan <>
   drivers/net/ethernet/mellanox/mlx4/cmd.c  | 11 +++++++++++
   drivers/net/ethernet/mellanox/mlx4/main.c | 11 +++++++++++
   include/linux/mlx4/device.h               |  1 +
   3 files changed, 23 insertions(+)

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