[linux-azure][hibernation] Mellanox CX4 NIC's TX/RX packets stop increasing after hibernation/resume

[Dexuan Cui]

[Impact]

Description of problem:
In a VM with CX4 VF NIC on Azure, after hibernation/resume, the TX/RX packet counters stop increaseing.
This issue doesn't exist in VM with a CX3 VF NIC.

This happens to the latest stable release of the linux-azure 5.4.0-1023.23 kernel and the latest mainline linux kernel.

[Test Case]

How reproducible:
100%

Steps to Reproduce:
1. Start a VM in Azure that supports Accelerated Networking, and enable hibernation properly (please refer to https://bugs.launchpad.net/ubuntu/+source/linux-azure/+bug/1880032/comments/14 ). Please make sure the VF NIC is CX-4 since the issue doesn't happen to CX-3.

2. Do hibernation from serial console
# systemctl hibernate

3. After the VM resumes back, check the MSI interrupt counters in /proc/interrupts for the CX-4 NIC, and also check “ifconfig” (e.g. “ifconfig enP2642s2”) for the RX/TX counters. These counters stop increasing while they should.

[Regression Potential]

The change touches netvsc and has potential to affect any instances using accelerated networking. However the fix is straightforward and it's a clean cherry-pick from 5.9.

[Other Info]

BUG FIX:
The fix is in the net.git tree now:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=19162fd4063a3211843b997a454b505edb81d5ce

[Dexuan Cui (decui)]

We also need the second and the third patch:

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=de214e52de1bba5392b5b7054924a08dbd57c2f6

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=da26658c3d7005aa67a706dceff7b2807b59e123

[Marcelo Cerri (mhcerri)]

SRU submission: https://lists.ubuntu.com/archives/kernel-team/2020-October/114296.html

[Marcelo Cerri (mhcerri)]

groovy:linux-azure already has the fix that was included by the upstream stable update LP:#1897550.

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-azure - 5.4.0-1032.33

---------------
linux-azure (5.4.0-1032.33) focal; urgency=medium

  * focal/linux-azure: 5.4.0-1032.33 -proposed tracker (LP: #1903162)

  * Focal update: v5.4.66 upstream stable release (LP: #1896824)
    - [Config] azure: updateconfigs for VGACON_SOFT_SCROLLBACK

  * [linux-azure][hibernation] Mellanox CX4 NIC's TX/RX packets stop increasing
    after hibernation/resume (LP: #1894896)
    - hv_netvsc: Fix hibernation for mlx5 VF driver

  * [linux-azure][hibernation] GPU device no longer working after resume from
    hibernation in NV6 VM size (LP: #1894893)
    - PCI: hv: Fix hibernation in case interrupts are not re-created

  * linux-azure: build and include the tcm_loop module to the main kernel
    package (LP: #1791794)
    - [Config] linux-azure: CONFIG_LOOPBACK_TARGET=m (tcm_loop)

  * [linux-azure] Two Fixes For kdump Over Network (LP: #1883261)
    - PCI: hv: Fix the PCI HyperV probe failure path to release resource properly
    - PCI: hv: Retry PCI bus D0 entry on invalid device state

  [ Ubuntu: 5.4.0-55.61 ]

  * focal/linux: 5.4.0-55.61 -proposed tracker (LP: #1903175)
  * Update kernel packaging to support forward porting kernels (LP: #1902957)
    - [Debian] Update for leader included in BACKPORT_SUFFIX
  * Avoid double newline when running insertchanges (LP: #1903293)
    - [Packaging] insertchanges: avoid double newline
  * EFI: Fails when BootCurrent entry does not exist (LP: #1899993)
    - efivarfs: Replace invalid slashes with exclamation marks in dentries.
  * CVE-2020-14351
    - perf/core: Fix race in the perf_mmap_close() function
  * raid10: Block discard is very slow, causing severe delays for mkfs and
    fstrim operations (LP: #1896578)
    - md: add md_submit_discard_bio() for submitting discard bio
    - md/raid10: extend r10bio devs to raid disks
    - md/raid10: pull codes that wait for blocked dev into one function
    - md/raid10: improve raid10 discard request
    - md/raid10: improve discard request for far layout
    - dm raid: fix discard limits for raid1 and raid10
    - dm raid: remove unnecessary discard limits for raid10
  * Bionic: btrfs: kernel BUG at /build/linux-
    eTBZpZ/linux-4.15.0/fs/btrfs/ctree.c:3233! (LP: #1902254)
    - btrfs: drop unnecessary offset_in_page in extent buffer helpers
    - btrfs: extent_io: do extra check for extent buffer read write functions
    - btrfs: extent-tree: kill BUG_ON() in __btrfs_free_extent()
    - btrfs: extent-tree: kill the BUG_ON() in insert_inline_extent_backref()
    - btrfs: ctree: check key order before merging tree blocks
  * Ethernet no link lights after reboot (Intel i225-v 2.5G) (LP: #1902578)
    - igc: Add PHY power management control
  * Undetected Data corruption in MPI workloads that use VSX for reductions on
    POWER9 DD2.1 systems (LP: #1902694)
    - powerpc: Fix undetected data corruption with P9N DD2.1 VSX CI load emulation
    - selftests/powerpc: Make alignment handler test P9N DD2.1 vector CI load
      workaround
  * [20.04 FEAT] Support/enhancement of NVMe IPL (LP: #1902179)
    - s390: nvme ipl
    - s390: nvme reipl
    - s390/ipl: support NVMe IPL kernel para...