CVE-2025-22086: RDMA/mlx5: Fix mlx5_poll_one() cur_qp update flow

Description

In the Linux kernel, the following vulnerability has been resolved:

RDMA/mlx5: Fix mlx5_poll_one() cur_qp update flow

When cur_qp isn't NULL, in order to avoid fetching the QP from
the radix tree again we check if the next cqe QP is identical to
the one we already have.

The bug however is that we are checking if the QP is identical by
checking the QP number inside the CQE against the QP number inside the
mlx5_ib_qp, but that's wrong since the QP number from the CQE is from
FW so it should be matched against mlx5_core_qp which is our FW QP
number.

Otherwise we could use the wrong QP when handling a CQE which could
cause the kernel trace below.

This issue is mainly noticeable over QPs 0 & 1, since for now they are
the only QPs in our driver whereas the QP number inside mlx5_ib_qp
doesn't match the QP number inside mlx5_core_qp.

BUG: kernel NULL pointer dereference, address: 0000000000000012
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP
CPU: 0 UID: 0 PID: 7927 Comm: kworker/u62:1 Not tainted 6.14.0-rc3+ #189
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
Workqueue: ib-comp-unb-wq ib_cq_poll_work [ib_core]
RIP: 0010:mlx5_ib_poll_cq+0x4c7/0xd90 [mlx5_ib]
Code: 03 00 00 8d 58 ff 21 cb 66 39 d3 74 39 48 c7 c7 3c 89 6e a0 0f b7 db e8 b7 d2 b3 e0 49 8b 86 60 03 00 00 48 c7 c7 4a 89 6e a0 <0f> b7 5c 98 02 e8 9f d2 b3 e0 41 0f ...

Classification

CVE ID: CVE-2025-22086

Affected Products

Vendor: Linux

Product: Linux, Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 8.02% (scored less or equal to compared to others)

EPSS Date: 2025-04-20 (when was this score calculated)

References

Timeline

2025-04-16 15:40:38 UTC
CVE

RDMA/mlx5: Fix mlx5_poll_one() cur_qp update flow