ALSA: pcm: Fix race between non-atomic ops and trigger-start

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89979
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:17:08 UTC
Updated2026-10-19 09:18:44 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 b1d12144557fceed5de6e22e2c2e30a40ed37702 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 b2edc017f94c08bdd0b046a586e43ac771a2f942 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 b599e7f16441386754ec083fa62a549bccb02fca git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 ad29779736cfd6f5595f0cab300dd7611418e363 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 5abeb4f9f2023f001d693b4e5e1ebbf25e25d0eb git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 7ad2ea7c10044b08ecf7b04376916faf12e17a99 git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 50afadf1ea66597116eb14e73c24da7ae99b759f git Not specified
CNA Linux Linux affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 acac7b5e07349a9d10d78873afb4b93cd1dc721f git Not specified
CNA Linux Linux affected 2.6.12 Not specified
CNA Linux Linux unaffected 2.6.12 semver Not specified
CNA Linux Linux unaffected 5.10.270 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.221 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/7ad2ea7c10044b08ecf7b04376916faf12e17a99 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/acac7b5e07349a9d10d78873afb4b93cd1dc721f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5abeb4f9f2023f001d693b4e5e1ebbf25e25d0eb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/50afadf1ea66597116eb14e73c24da7ae99b759f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b2edc017f94c08bdd0b046a586e43ac771a2f942 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b599e7f16441386754ec083fa62a549bccb02fca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b1d12144557fceed5de6e22e2c2e30a40ed37702 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ad29779736cfd6f5595f0cab300dd7611418e363 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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