io_uring: defer eventfd signaling when queued from a wakeup handler

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80920
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-09 17:17:47 UTC
Updated2026-09-09 17:17:47 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 21a091b970cdbcf3e8ff829234b51be6f9192766 e22f4494cc9487d326e5e3067f33dea7c1e442b2 git Not specified
CNA Linux Linux affected 21a091b970cdbcf3e8ff829234b51be6f9192766 b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f git Not specified
CNA Linux Linux affected 21a091b970cdbcf3e8ff829234b51be6f9192766 40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a git Not specified
CNA Linux Linux affected 21a091b970cdbcf3e8ff829234b51be6f9192766 cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e git Not specified
CNA Linux Linux affected 6.1 Not specified
CNA Linux Linux unaffected 6.1 semver Not specified
CNA Linux Linux unaffected 6.18.49 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.11 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2.1 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e22f4494cc9487d326e5e3067f33dea7c1e442b2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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