RDMA/mlx5: Fix the recovery flow of the UMR QP
概要
RDMA/mlx5: Fix the recovery flow of the UMR QP
原文の説明
取得元が公開している説明をそのまま載せています (多くは英語)。
In the Linux kernel, the following vulnerability has been resolved:
RDMA/mlx5: Fix the recovery flow of the UMR QP
This patch addresses an issue in the recovery flow of the UMR QP,
ensuring tasks do not get stuck, as highlighted by the call trace [1].
During recovery, before transitioning the QP to the RESET state, the
software must wait for all outstanding WRs to complete.
Failing to do so can cause the firmware to skip sending some flushed
CQEs with errors and simply discard them upon the RESET, as per the IB
specification.
This race condition can result in lost CQEs and tasks becoming stuck.
To resolve this, the patch sends a final WR which serves only as a
barrier before moving the QP state to RESET.
Once a CQE is received for that final WR, it guarantees that no
outstanding WRs remain, making it safe to transition the QP to RESET and
subsequently back to RTS, restoring proper functionality.
Note:
For the barrier WR, we simply reuse the failed and ready WR.
Since the QP is in an error state, it will only receive
IB_WC_WR_FLUSH_ERR. However, as it serves only as a barrier we don't
care about its status.
[1]
INFO: task rdma_resource_l:1922 blocked for more than 120 seconds.
Tainted: G W 6.12.0-rc7+ #1626
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:rdma_resource_l state:D stack:0 pid:1922 tgid:1922 ppid:1369
flags:0x00004004
Call Trace:
__schedule+0x420/0xd30
schedule+0x47/0x130
schedule_timeout+0x280/0x300…
影響パッケージ
ディストリビューション別の修正状況
各ディストリビューションが公開している、この CVE の修正パッケージ
- BellSoft Alpaquita BELL-CVE-2025-21892 linux-lts
- Debian DEBIAN-CVE-2025-21892 linux
- Ubuntu UBUNTU-CVE-2025-21892 linux-hwe-edge
参照URL
- advisory github.com
- advisory nvd.nist.gov
- package git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org