io_uring/cancel: rearm local work wake up before sleep

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-99253
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-11-03 12:17:32 UTC
Updated2026-11-06 18:18:33 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: io_uring/cancel: rearm local work wake up before sleep io_uring_try_cancel_requests() sets ->cq_wait_nr to 1 so that the next io_req_local_work_add() wakes the cancelling task. The add that takes the count to zero is the only one that wakes, later ones see a count <= 0 and return. io_uring_cancel_generic() however only becomes TASK_INTERRUPTIBLE much later, so the one wake up can be spent on a running task. That is fine as long as the entry of that add is still queued, as the io_local_work_pending() check then skips the sleep. It is not if the add was delayed after queueing its entry: CPU0 (submitter in exec or exit) CPU1 (io_req_local_work_add) mpscq_push(req A) io_uring_try_cancel_requests() io_run_local_work() // runs req A io_uring_try_cancel_requests() atomic_set(&ctx->cq_wait_nr, 1) atomic_read(&ctx->cq_wait_nr) == 1 count taken, wake_up_state() // task is running, no-op prepare_to_wait(TASK_INTERRUPTIBLE) io_local_work_pending() == false schedule() mpscq_push(req B) cq_wait_nr <= 0, return Only the sleeping task can run req B, so it is stuck in execve() until a signal happens to wake it. An exiting task doesn't even get that. Arm the count again once the task state is set and before the work list is checked, for the rings whose local work this task is the one to run.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected d46ab2c98ababa19b41a5709b6921d7b1add7f74 aaa06bb9fc03384f7cf2dbc3e43f2939cc7791b2 git Not specified
CNA Linux Linux affected d46ab2c98ababa19b41a5709b6921d7b1add7f74 58ddf0ec707093206a5fe814581ec5aefac8b08a git Not specified
CNA Linux Linux affected d46ab2c98ababa19b41a5709b6921d7b1add7f74 76a82c666abf155ad52d5f41043eac77dd3e41d8 git Not specified
CNA Linux Linux affected 7.2 Not specified
CNA Linux Linux unaffected 7.2 semver Not specified
CNA Linux Linux unaffected 7.2.14 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3.2 7.3.* semver Not specified
CNA Linux Linux unaffected 7.4-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/aaa06bb9fc03384f7cf2dbc3e43f2939cc7791b2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/76a82c666abf155ad52d5f41043eac77dd3e41d8 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/58ddf0ec707093206a5fe814581ec5aefac8b08a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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