CVE-2026-99256
dm cache: fix issue with background work locking
In the Linux kernel, the following vulnerability has been resolved: dm cache: fix issue with background work locking dm cache used a rw_semaphore for background_work_lock. Write locks on rw_semaphores have strict owner semantics, but there was no guarantee that the process that locked background_work_lock was the same process that unlocked it. This can be easily seen using a kernel compiled with CONFIG_DEBUG_RWSEMS. Given a dm cache device <cache>, run: 'dmsetup suspend <cache> && dmsetup resume <cache>'. This will trigger a kernel warning: DEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE)) triggered by cache_resume(). To fix this, switch from a rw_semaphore to a spinlock and a wait queue. dm cache already has a wait queue and associated counter, migration_wait and nr_allocated_migrations, that was getting woken up when background work was getting completed, but wasn't actually used by anything. This is replaced by the background_work queue and counter.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| Linux Linux |
≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 0c7a8cad7c96012a9157a189649e569d0390f384 (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < f5db935d257023c3ef410bd39163b949b0e5a55d (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 6290507ecc0dd6dd40759729cbbbd49b1d2a63c4 (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 8433fd005c25fd127021f67c9144a879fb585572 (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 2f2cfa16dd0f4179bb988139dd37d00a42324f6c (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 73df2ff409f3db95029982fe3656329568e3715d (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < 104f09e02038b0fc6bbb718b3976af029e15c1d0 (affected, git) ≥ b29d4986d0da1a27cd35917cdb433672f5c95d7f; < bc9781c0247de107876f32929f1637db93a42b34 (affected, git) Other versions: unaffected |
CNA: Linux |
| Linux Linux |
4.12 (affected) ≥ 0; < 4.12 (unaffected, semver) ≥ 5.10.273; ≤ 5.10.* (unaffected, semver) ≥ 5.15.224; ≤ 5.15.* (unaffected, semver) ≥ 6.1.191; ≤ 6.1.* (unaffected, semver) ≥ 6.6.161; ≤ 6.6.* (unaffected, semver) ≥ 6.12.115; ≤ 6.12.* (unaffected, semver) ≥ 6.18.59; ≤ 6.18.* (unaffected, semver) ≥ 7.2.13; ≤ 7.2.* (unaffected, semver) ≥ 7.3; ≤ * (unaffected, original_commit_for_fix) Other versions: affected |
CNA: Linux |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
No CVSS assessment reported. An unscored record is not a low-severity determination.
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://git.kernel.org/stable/c/0c7a8cad7c96012a9157a189649e569d0390f384CNA: Linux
- https://git.kernel.org/stable/c/f5db935d257023c3ef410bd39163b949b0e5a55dCNA: Linux
- https://git.kernel.org/stable/c/6290507ecc0dd6dd40759729cbbbd49b1d2a63c4CNA: Linux
- https://git.kernel.org/stable/c/8433fd005c25fd127021f67c9144a879fb585572CNA: Linux
- https://git.kernel.org/stable/c/2f2cfa16dd0f4179bb988139dd37d00a42324f6cCNA: Linux
- https://git.kernel.org/stable/c/73df2ff409f3db95029982fe3656329568e3715dCNA: Linux
- https://git.kernel.org/stable/c/104f09e02038b0fc6bbb718b3976af029e15c1d0CNA: Linux
- https://git.kernel.org/stable/c/bc9781c0247de107876f32929f1637db93a42b34CNA: Linux
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