FKIE_CVE-2026-99256

Vulnerability from fkie_nvd - Published: 2026-11-03 12:17 - Updated: 2026-11-03 12:17
Severity
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0c7a8cad7c96012a9157a189649e569d0390f384
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/104f09e02038b0fc6bbb718b3976af029e15c1d0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/2f2cfa16dd0f4179bb988139dd37d00a42324f6c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6290507ecc0dd6dd40759729cbbbd49b1d2a63c4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/73df2ff409f3db95029982fe3656329568e3715d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8433fd005c25fd127021f67c9144a879fb585572
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bc9781c0247de107876f32929f1637db93a42b34
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f5db935d257023c3ef410bd39163b949b0e5a55d
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-cache-target.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0c7a8cad7c96012a9157a189649e569d0390f384",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "f5db935d257023c3ef410bd39163b949b0e5a55d",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "6290507ecc0dd6dd40759729cbbbd49b1d2a63c4",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "8433fd005c25fd127021f67c9144a879fb585572",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "2f2cfa16dd0f4179bb988139dd37d00a42324f6c",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "73df2ff409f3db95029982fe3656329568e3715d",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "104f09e02038b0fc6bbb718b3976af029e15c1d0",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            },
            {
              "lessThan": "bc9781c0247de107876f32929f1637db93a42b34",
              "status": "affected",
              "version": "b29d4986d0da1a27cd35917cdb433672f5c95d7f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/md/dm-cache-target.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
            {
              "lessThan": "4.12",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.273",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.224",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.191",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.161",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.115",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.59",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 \u003ccache\u003e, run: \u0027dmsetup\nsuspend \u003ccache\u003e \u0026\u0026 dmsetup resume \u003ccache\u003e\u0027. This will trigger a kernel\nwarning:\n\nDEBUG_RWSEMS_WARN_ON((rwsem_owner(sem) != current) \u0026\u0026 !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\u0027t\nactually used by anything. This is replaced by the background_work queue\nand counter."
    }
  ],
  "id": "CVE-2026-99256",
  "lastModified": "2026-11-03T12:17:32.437",
  "metrics": {},
  "published": "2026-11-03T12:17:32.437",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "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"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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