CVE-2024-40925

/// Technical description

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

block: fix request.queuelist usage in flush

Friedrich Weber reported a kernel crash problem and bisected to commit

81ada09cc25e ("blk-flush: reuse rq queuelist in flush state machine").

The root cause is that we use "list_move_tail(&rq->queuelist, pending)"

in the PREFLUSH/POSTFLUSH sequences. But rq->queuelist.next == xxx since

it's popped out from plug->cached_rq in __blk_mq_alloc_requests_batch().

We don't initialize its queuelist just for this first request, although

the queuelist of all later popped requests will be initialized.

Fix it by changing to use "list_add_tail(&rq->queuelist, pending)" so

rq->queuelist doesn't need to be initialized. It should be ok since rq

can't be on any list when PREFLUSH or POSTFLUSH, has no move actually.

Please note the commit 81ada09cc25e ("blk-flush: reuse rq queuelist in

flush state machine") also has another requirement that no drivers would

touch rq->queuelist after blk_m

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References