f2fs: avoid NULL checkpoint thread access in sysfs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89835
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:16:50 UTC
Updated2026-09-16 11:16:50 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: f2fs: avoid NULL checkpoint thread access in sysfs checkpoint_merge can be enabled even when no checkpoint merge thread is running. A read-only mount is one case: f2fs does not start f2fs_issue_ckpt there, but ckpt_thread_ioprio is still writable through sysfs. The ckpt_thread_ioprio store path updates the saved ioprio value and, when checkpoint_merge is enabled, calls set_task_ioprio() for the checkpoint thread. If cprc->f2fs_issue_ckpt is NULL, that dereferences a NULL task pointer. Protect ckpt_thread_ioprio sysfs writes with s_umount as well, so the checkpoint thread cannot disappear under the store path while updating its ioprio.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected e65920661708b7c0f3db45c9cd5d0095034ee37f a6573f3ffc19542de9ebc1a2b1f930fd48ba538c git Not specified
CNA Linux Linux affected e65920661708b7c0f3db45c9cd5d0095034ee37f aefcec3bebdeed2bff444378122300763325ba23 git Not specified
CNA Linux Linux affected e65920661708b7c0f3db45c9cd5d0095034ee37f 8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b git Not specified
CNA Linux Linux affected e65920661708b7c0f3db45c9cd5d0095034ee37f 5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f git Not specified
CNA Linux Linux affected 5.12 Not specified
CNA Linux Linux unaffected 5.12 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-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/8f3b99c50dd0da1777994ce7c7e60d39b9f60f4b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5cb33b00c8fbb6e8f1fa3d281c3036d5f7c7c41f 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/aefcec3bebdeed2bff444378122300763325ba23 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/a6573f3ffc19542de9ebc1a2b1f930fd48ba538c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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