Paper/Archive/CVE-2026-89681

CVE-2026-89681

Linux Linux — nfsd: fix layout fence worker double-reference race

Description · from the CVE record

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix layout fence worker double-reference race The workqueue core clears WORK_STRUCT_PENDING before the callback is invoked, so delayed_work_pending() in lm_breaker_timedout() can return false while the fence worker is already running. This lets the breaker take a duplicate sc_count reference and schedule a new worker that coalesces with the in-progress one. The extra reference is never put, leaking the layout stateid. Replace the racy delayed_work_pending() check with an ls_fence_inflight boolean set atomically with refcount_inc_not_zero() under ls_lock, and cleared under ls_lock before the final nfs4_put_stid() on the dispose path; the retry path intentionally retains it. Remove the self-rearm mod_delayed_work() at the top of the worker.

Affected

ProductAffectedFixed inSource
Linuxf52792f484ba2316853736856dde19b7e7458861 – < a278d361e0e8f242211891193d56483a7a9f47a8a278d361e0e8f242211891193d56483a7a9f47a8CNA
Linuxf52792f484ba2316853736856dde19b7e7458861 – < 8580571227451384399b3fa53fcde19848c48e5a8580571227451384399b3fa53fcde19848c48e5aCNA
Linux7.17.2.4CNA

Scores by source

Linux (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

refgit.kernel.org/stable/c/a278d361e0e8f242211891193d56483a7a9f47a8refgit.kernel.org/stable/c/8580571227451384399b3fa53fcde19848c48e5a