[linux-azure] [SRU] UBUNTU: SAUCE: Drivers: hv: vmbus: Add timeout to vmbus_wait_for_unload

Bug #1895527 reported by Joseph Salisbury on 2020-09-14
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux-azure (Ubuntu)
Status tracked in Groovy
Bionic
High
Marcelo Cerri
Focal
High
Marcelo Cerri
Groovy
High
Marcelo Cerri
linux-azure-4.15 (Ubuntu)
Status tracked in Groovy
Bionic
High
Marcelo Cerri
Focal
High
Marcelo Cerri
Groovy
Undecided
Marcelo Cerri

Bug Description

[Impact]

This is a request to inclue a patch, submitted to the upstream linux-hyperv mailing list, in the linux-azure kernels.

Microsoft would like to request this patch in the 16.04 (4.15) and newer azure kernels. This patch fixes a prior commit, hence the SRU request:

Fixes: 415719160de3 ("Drivers: hv: vmbus: avoid scheduling in interrupt context in vmbus_initiate_unload()")

The patch specfically performs the following:

"vmbus_wait_for_unload() looks for a CHANNELMSG_UNLOAD_RESPONSE message coming from Hyper-V. But if the message isn't found for some reason, the panic path gets hung forever. Add a timeout of 10 seconds to prevent this."

The requested patch can be found at:
https://lkml.org/lkml/2020/9/13/196

[Test Case]

Since the problem depends on a communication failure with the host. I recommend testing for regressions. The change affects when the module is removed or the system is suspended.

[Regression Potential]

The change affects the panic path and suspend so any regressions shouldn't be critical.

Marcelo Cerri (mhcerri) on 2020-09-17
Changed in linux-azure (Ubuntu Bionic):
status: New → Invalid
Changed in linux-azure-4.15 (Ubuntu Focal):
status: New → Invalid
Changed in linux-azure-4.15 (Ubuntu Groovy):
status: New → Invalid
Changed in linux-azure-4.15 (Ubuntu Bionic):
status: New → In Progress
Changed in linux-azure (Ubuntu Focal):
status: New → In Progress
Changed in linux-azure (Ubuntu Groovy):
status: New → In Progress
Changed in linux-azure (Ubuntu Bionic):
importance: Undecided → High
Changed in linux-azure (Ubuntu Focal):
importance: Undecided → High
Changed in linux-azure (Ubuntu Groovy):
importance: Undecided → High
Changed in linux-azure-4.15 (Ubuntu Bionic):
importance: Undecided → High
Changed in linux-azure (Ubuntu Bionic):
assignee: nobody → Marcelo Cerri (mhcerri)
Changed in linux-azure-4.15 (Ubuntu Focal):
importance: Undecided → High
Changed in linux-azure (Ubuntu Focal):
assignee: nobody → Marcelo Cerri (mhcerri)
Changed in linux-azure-4.15 (Ubuntu Bionic):
assignee: nobody → Marcelo Cerri (mhcerri)
Changed in linux-azure-4.15 (Ubuntu Focal):
assignee: nobody → Marcelo Cerri (mhcerri)
Changed in linux-azure-4.15 (Ubuntu Groovy):
assignee: nobody → Marcelo Cerri (mhcerri)
Changed in linux-azure (Ubuntu Groovy):
assignee: nobody → Marcelo Cerri (mhcerri)
Marcelo Cerri (mhcerri) on 2020-09-17
description: updated
Changed in linux-azure (Ubuntu Focal):
status: In Progress → Fix Committed
Changed in linux-azure-4.15 (Ubuntu Bionic):
status: In Progress → Fix Committed
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