{"id":"CVE-2026-53062","title":"dm cache policy smq: fix missing locks in invalidating cache blocks","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm cache policy smq: fix missing locks in invalidating cache blocks\n\nIn passthrough mode, the policy invalidate_mapping operation is called\nsimultaneously from multiple…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 4991b5a08751e2e82488fb93ae08849b6aea10d9","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 1b2bec4a7dcf5f00b7a1cbeeec8997841d783513","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 9a5fdfb9e57ec3a8ad2b8fce5e5ffa42d53b130e","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < ac5ee99443891bdb161f5539606a66a1b5e72542","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 93627a29d4b66d4a2def938dfb8610cc80ae454b","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < c348ae47d8e65f06429fa41adce9ad986b696766","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 2b62d0611c9af14a16bddf22df2612b4f40eb5a1","Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 2d1f7b65f5deedd2e6b09fdc6ea27f8375f24b45","Linux 4.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:24:58.631300Z"},"published":"2026-06-24","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:31:29.953Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-53062","references":[{"url":"https://git.kernel.org/stable/c/4991b5a08751e2e82488fb93ae08849b6aea10d9"},{"url":"https://git.kernel.org/stable/c/1b2bec4a7dcf5f00b7a1cbeeec8997841d783513"},{"url":"https://git.kernel.org/stable/c/9a5fdfb9e57ec3a8ad2b8fce5e5ffa42d53b130e"},{"url":"https://git.kernel.org/stable/c/ac5ee99443891bdb161f5539606a66a1b5e72542"},{"url":"https://git.kernel.org/stable/c/93627a29d4b66d4a2def938dfb8610cc80ae454b"},{"url":"https://git.kernel.org/stable/c/c348ae47d8e65f06429fa41adce9ad986b696766"},{"url":"https://git.kernel.org/stable/c/2b62d0611c9af14a16bddf22df2612b4f40eb5a1"},{"url":"https://git.kernel.org/stable/c/2d1f7b65f5deedd2e6b09fdc6ea27f8375f24b45"}],"tags":["cve.org"],"epss":0.00097,"epssPercentile":0.00699,"ingestedAt":"2026-10-16T17:24:46.728Z","slug":"CVE-2026-53062","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ndm cache policy smq: fix missing locks in invalidating cache blocks\n\nIn passthrough mode, the policy invalidate_mapping operation is called\nsimultaneously from multiple workers, thus it should be protected by a\nlock. Otherwise, we might end up with data races on the allocated blocks\ncounter, or even use-after-free issues with internal data structures\nwhen doing concurrent writes.\n\nNote that the existing FIXME in smq_invalidate_mapping() doesn't affect\npassthrough mode since migration tasks don't exist there, but would need\nattention if supporting fast device shrinking via suspend/resume without\ntarget reloading.\n\nReproduce steps:\n\n1. Create a cache device consisting of 1024 cache entries\n\ndmsetup create cmeta --table \"0 8192 linear /dev/sdc 0\"\ndmsetup create cdata --table \"0 131072 linear /dev/sdc 8192\"\ndmsetup create corig --table \"0 262144 linear /dev/sdc 262144\"\ndd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct\ndmsetup create cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0\"\n\n2. Populate the cache, and record the number of cached blocks\n\nfio --name=populate --filename=/dev/mapper/cache --rw=randwrite --bs=4k \\\n--size=64m --direct=1\nnr_cached=$(dmsetup status cache | awk '{split($7, a, \"/\"); print a[1]}')\n\n3. Reload the cache into passthrough mode\n\ndmsetup suspend cache\ndmsetup reload cache --table \"0 262144 cache /dev/mapper/cmeta \\\n/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0\"\ndmsetup resume cache\n\n4. Write to the passthrough cache. By setting multiple jobs with I/O\n   size equal to the cache block size, cache blocks are invalidated\n   concurrently from different workers.\n\nfio --filename=/dev/mapper/cache --name=test --rw=randwrite --bs=64k \\\n--direct=1 --numjobs=2 --randrepeat=0 --size=64m\n\n5. Check if demoted matches cached block count. These numbers should\n   match but may differ due to the data race.\n\nnr_demoted=$(dmsetup status cache | awk '{print $12}')\necho \"$nr_cached, $nr_demoted\"\n\n## Affected\n\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 4991b5a08751e2e82488fb93ae08849b6aea10d9`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 1b2bec4a7dcf5f00b7a1cbeeec8997841d783513`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 9a5fdfb9e57ec3a8ad2b8fce5e5ffa42d53b130e`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < ac5ee99443891bdb161f5539606a66a1b5e72542`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 93627a29d4b66d4a2def938dfb8610cc80ae454b`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < c348ae47d8e65f06429fa41adce9ad986b696766`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 2b62d0611c9af14a16bddf22df2612b4f40eb5a1`\n- `Linux >= b29d4986d0da1a27cd35917cdb433672f5c95d7f < 2d1f7b65f5deedd2e6b09fdc6ea27f8375f24b45`\n- `Linux 4.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}