CVE-2026-89979
Description
In the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: Fix race between non-atomic ops and trigger-start We protect the races of the concurrent state transitions between atomic PCM ops, but the checks between the non-atomic ops (hw_params, hw_free and prepare) and the atomic ops aren't perfect; there is a check of the conflicting PCM state at the beginning of hw_params & co, but the atomic PCM ops can be still issued during the non-atomic PCM operations. An example such scenario is that a thread A re-issues the PREPARE or HW_PARAMS for the already prepared stream, while another thread B triggers the PCM start in the middle of the prepare operation. Although this usually doesn't lead to much serious issues, it can give some inconsistency as reported by syzkaller (such as ODEBUG warning). There are various atomic PCM ops, and basically the only problem is the PCM start as it operates from the PREPARED state. Other trigger commands (stop, etc) are for the running or the other special state, hence they are filtered as pre-condition. This patch is for preventing the PCM trigger-start during the non- atomic operations in order to address the problems above. Fortunately, the hw_params, hw_free and prepare operations call snd_pcm_buffer_access_lock(), and this can be used for checking the concurrent operations at the PCM trigger -- which sets the runtime->buffer_accessing to a negative (if possible), so the PCM trigger just needs to check the runtime->buffer_accessing value; if it's negative, it means the concurrent non-atomic PCM ops is running.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://git.kernel.org/stable/c/50afadf1ea66597116eb14e73c24da7ae99b759f
- https://git.kernel.org/stable/c/5abeb4f9f2023f001d693b4e5e1ebbf25e25d0eb
- https://git.kernel.org/stable/c/7ad2ea7c10044b08ecf7b04376916faf12e17a99
- https://git.kernel.org/stable/c/acac7b5e07349a9d10d78873afb4b93cd1dc721f
- https://git.kernel.org/stable/c/ad29779736cfd6f5595f0cab300dd7611418e363
- https://git.kernel.org/stable/c/b1d12144557fceed5de6e22e2c2e30a40ed37702
- https://git.kernel.org/stable/c/b2edc017f94c08bdd0b046a586e43ac771a2f942
- https://git.kernel.org/stable/c/b599e7f16441386754ec083fa62a549bccb02fca
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.