mlxbf-tmfifo: fix potential race

[Liming Sun]

SRU Justification:

[Impact]
This change is needed to avoid potential race of accessing the 'vq' pointer

[Fix]
The fix adds memory barrier for the is_ready flag and the 'vq' pointer access in mlxbf_tmfifo_virtio_find_vqs(), so updated in vq will be visible before accessing this pointer.

[Test Case]
Same functionality and testing as on BlueField-1/2/2. No functionality change.

[Regression Potential]
Same behavior from user perspective.

[Bartlomiej Zolnierkiewicz (bzolnier)]

This bug is awaiting verification that the linux-bluefield/5.15.0-1019.21 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-jammy' to 'verification-done-jammy'. If the problem still exists, change the tag 'verification-needed-jammy' to 'verification-failed-jammy'.

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 https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is awaiting verification that the linux-bluefield/5.4.0-1068.74 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-focal' to 'verification-done-focal'. If the problem still exists, change the tag 'verification-needed-focal' to 'verification-failed-focal'.

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 https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux-bluefield - 5.4.0-1068.74

---------------
linux-bluefield (5.4.0-1068.74) focal; urgency=medium

  * focal/linux-bluefield: 5.4.0-1068.74 -proposed tracker (LP: #2026552)

  * mlxbf-tmfifo: fix potential race (LP: #2016039)
    - SAUCE: mlxbf-tmfifo: fix potential race

  * mlxbf-gige: Fix kernel panic at shutdown (LP: #2022370)
    - SAUCE: mlxbf-gige: Fix kernel panic at shutdown

  * net: openvswitch: fix race on port output (LP: #2020606)
    - net: openvswitch: fix race on port output

  * mlxbf-bootctl: support SMC call for setting ARM boot state (LP: #2013383)
    - SAUCE: mlxbf-bootctl: support SMC call for setting ARM boot state

  * mlxbf-gige: Fix intermittent no ip issue (LP: #2022387)
    - SAUCE: mlxbf-gige: Fix intermittent no ip issue

  * mlxbf-tmfifo: robust fix to drop over-sized packet or no Rx descriptors
    (LP: #2021749)
    - SAUCE: mlxbf-tmfifo: Drop the Rx packet if no more descriptors
    - SAUCE: mlxbf-tmfifo: Drop jumbo frames

  [ Ubuntu: 5.4.0-156.173 ]

  * focal/linux: 5.4.0-156.173 -proposed tracker (LP: #2026585)
  * CVE-2023-3390
    - netfilter: nf_tables: incorrect error path handling with NFT_MSG_NEWRULE
  * Focal update: v5.4.241 upstream stable release (LP: #2023930)
    - scsi: ses: Handle enclosure with just a primary component gracefully
    - x86/PCI: Add quirk for AMD XHCI controller that loses MSI-X state in D3hot
    - cgroup/cpuset: Wake up cpuset_attach_wq tasks in cpuset_cancel_attach()
    - treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()
    - smb3: fix problem with null cifs super block with previous patch
    - pinctrl: amd: Use irqchip template
    - pinctrl: amd: disable and mask interrupts on probe
    - pinctrl: amd: Disable and mask interrupts on resume
    - pwm: cros-ec: Explicitly set .polarity in .get_state()
    - pwm: sprd: Explicitly set .polarity in .get_state()
    - wifi: mac80211: fix invalid drv_sta_pre_rcu_remove calls for non-uploaded
      sta
    - icmp: guard against too small mtu
    - net: don't let netpoll invoke NAPI if in xmit context
    - sctp: check send stream number after wait_for_sndbuf
    - ipv6: Fix an uninit variable access bug in __ip6_make_skb()
    - gpio: davinci: Add irq chip flag to skip set wake
    - sunrpc: only free unix grouplist after RCU settles
    - NFSD: callback request does not use correct credential for AUTH_SYS
    - xhci: also avoid the XHCI_ZERO_64B_REGS quirk with a passthrough iommu
    - USB: serial: cp210x: add Silicon Labs IFS-USB-DATACABLE IDs
    - usb: typec: altmodes/displayport: Fix configure initial pin assignment
    - USB: serial: option: add Telit FE990 compositions
    - USB: serial: option: add Quectel RM500U-CN modem
    - iio: adc: ti-ads7950: Set `can_sleep` flag for GPIO chip
    - iio: dac: cio-dac: Fix max DAC write value check for 12-bit
    - tty: serial: sh-sci: Fix transmit end interrupt handler
    - tty: serial: sh-sci: Fix Rx on RZ/G2L SCI
    - tty: serial: fsl_lpuart: avoid checking for transfer complete when
      UARTCTRL_SBK is asserted in lpuart32_tx_empty
    - nilfs2: fix potential UAF of struct nilfs_sc_info in nilfs_segctor_thread()
   ...