{"identifier":"CVE-2026-99256","cve":{"id":"CVE-2026-99256","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache: fix issue with background work locking\n\ndm cache used a rw_semaphore for background_work_lock. Write locks on\nrw_semaphores have strict owner semantics, but there was no guarantee\nthat the process that locked background_work_lock was the same process\nthat unlocked it. This can be easily seen using a kernel compiled with\nCONFIG_DEBUG_RWSEMS. Given a dm cache device <cache>, run: 'dmsetup\nsuspend <cache> && dmsetup resume <cache>'. This will trigger a kernel\nwarning:\n\nDEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) && !rwsem_test_oflags(sem, RWSEM_NONSPINNABLE))\n\ntriggered by cache_resume(). To fix this, switch from a rw_semaphore to\na spinlock and a wait queue. dm cache already has a wait queue and\nassociated counter, migration_wait and nr_allocated_migrations, that was\ngetting woken up when background work was getting completed, but wasn't\nactually used by anything. This is replaced by the background_work queue\nand counter.","published":"2026-11-03T12:17:32.437000+00:00","modified":"2026-11-03T12:17:32.437000+00:00","status":"Received","score":null,"severity":"UNSCORED","vector":"","cvss_version":"","affected":[],"weaknesses":[],"references":[{"url":"https://git.kernel.org/stable/c/0c7a8cad7c96012a9157a189649e569d0390f384","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/104f09e02038b0fc6bbb718b3976af029e15c1d0","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2f2cfa16dd0f4179bb988139dd37d00a42324f6c","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6290507ecc0dd6dd40759729cbbbd49b1d2a63c4","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/73df2ff409f3db95029982fe3656329568e3715d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/8433fd005c25fd127021f67c9144a879fb585572","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bc9781c0247de107876f32929f1637db93a42b34","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f5db935d257023c3ef410bd39163b949b0e5a55d","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"kev":null,"kev_checked":true,"metrics":{},"configurations":[],"source":"nvd","retrieved_at":"2026-11-03T15:35:05.831637+00:00","exploited":false,"kev_stale":false,"products":[],"priority":{"label":"Assess exposure and vendor guidance","reasons":["No higher-priority signal is available in the current stored evidence.","Fresh EPSS data is unavailable; missing values are not zero."]},"epss":null,"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"git.kernel.org","source_url":"https://git.kernel.org/stable/c/0c7a8cad7c96012a9157a189649e569d0390f384","investigate_url":"https://investigate.aeglixmind.com/#git.kernel.org"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-99256","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-99256","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-99256","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}