{"api_version":"1","generated_at":"2026-08-02T09:03:46+00:00","cve":"CVE-2026-64419","urls":{"html":"https://cve.report/CVE-2026-64419","api":"https://cve.report/api/cve/CVE-2026-64419.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64419","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64419"},"summary":{"title":"mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()\n\nReading the debugfs \"count\" file of a memcg-aware shrinker can sleep\ninside an RCU read-side critical section:\n\n  BUG: sleeping function called from invalid context at kernel/cgroup/rstat.c:421\n  RCU nest depth: 1, expected: 0\n   css_rstat_flush\n   mem_cgroup_flush_stats\n   zswap_shrinker_count\n   shrinker_debugfs_count_show\n\nshrinker_debugfs_count_show() invokes the ->count_objects() callback under\nrcu_read_lock().  The zswap callback flushes memcg stats via\ncss_rstat_flush(), which may sleep, so it must not run under RCU.\n\nThe RCU lock is not needed here.  mem_cgroup_iter() takes RCU internally\nand returns a memcg holding a css reference (dropped on the next iteration\nor by mem_cgroup_iter_break()), so the memcg stays alive without it.  The\nshrinker is kept alive by the open debugfs file: shrinker_free() removes\nthe debugfs entries via debugfs_remove_recursive(), which waits for\nin-flight readers to drain, before call_rcu(..., shrinker_free_rcu_cb). \nThe sibling \"scan\" handler already invokes the sleeping ->scan_objects()\ncallback with no RCU section.\n\nDrop the rcu_read_lock()/rcu_read_unlock().","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-25 10:17:25","updated_at":"2026-07-25 10:17:25"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/86237e56091e70f09c0fbf217f9d9c0e08f556c4","name":"https://git.kernel.org/stable/c/86237e56091e70f09c0fbf217f9d9c0e08f556c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e441cbfbd0eaa6404278e985033c33caba4db767","name":"https://git.kernel.org/stable/c/e441cbfbd0eaa6404278e985033c33caba4db767","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/de5f69b8dae8698ac5e48dfcd30017887cdf4e5a","name":"https://git.kernel.org/stable/c/de5f69b8dae8698ac5e48dfcd30017887cdf4e5a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/b902890c62d200b3509cb5e09cf1e0a66553c128","name":"https://git.kernel.org/stable/c/b902890c62d200b3509cb5e09cf1e0a66553c128","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2fed79f0fe8c8d28a972c290dbfd693c3546c8c4","name":"https://git.kernel.org/stable/c/2fed79f0fe8c8d28a972c290dbfd693c3546c8c4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/560e21e8ccff813e84d05f6500907c549a3d6985","name":"https://git.kernel.org/stable/c/560e21e8ccff813e84d05f6500907c549a3d6985","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64419","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64419","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 de5f69b8dae8698ac5e48dfcd30017887cdf4e5a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 e441cbfbd0eaa6404278e985033c33caba4db767 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 2fed79f0fe8c8d28a972c290dbfd693c3546c8c4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 560e21e8ccff813e84d05f6500907c549a3d6985 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 86237e56091e70f09c0fbf217f9d9c0e08f556c4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5035ebc644aec92d55d1bbfe042f35341e4bffb5 b902890c62d200b3509cb5e09cf1e0a66553c128 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.0","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.0 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.178 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.145 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"64419","cve":"CVE-2026-64419","epss":"0.001730000","percentile":"0.069630000","score_date":"2026-07-28","updated_at":"2026-07-29 00:05:33"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["mm/shrinker_debug.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"de5f69b8dae8698ac5e48dfcd30017887cdf4e5a","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"},{"lessThan":"e441cbfbd0eaa6404278e985033c33caba4db767","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"},{"lessThan":"2fed79f0fe8c8d28a972c290dbfd693c3546c8c4","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"},{"lessThan":"560e21e8ccff813e84d05f6500907c549a3d6985","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"},{"lessThan":"86237e56091e70f09c0fbf217f9d9c0e08f556c4","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"},{"lessThan":"b902890c62d200b3509cb5e09cf1e0a66553c128","status":"affected","version":"5035ebc644aec92d55d1bbfe042f35341e4bffb5","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["mm/shrinker_debug.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.0"},{"lessThan":"6.0","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.178","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.145","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.178","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.145","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"6.0","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"6.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()\n\nReading the debugfs \"count\" file of a memcg-aware shrinker can sleep\ninside an RCU read-side critical section:\n\n  BUG: sleeping function called from invalid context at kernel/cgroup/rstat.c:421\n  RCU nest depth: 1, expected: 0\n   css_rstat_flush\n   mem_cgroup_flush_stats\n   zswap_shrinker_count\n   shrinker_debugfs_count_show\n\nshrinker_debugfs_count_show() invokes the ->count_objects() callback under\nrcu_read_lock().  The zswap callback flushes memcg stats via\ncss_rstat_flush(), which may sleep, so it must not run under RCU.\n\nThe RCU lock is not needed here.  mem_cgroup_iter() takes RCU internally\nand returns a memcg holding a css reference (dropped on the next iteration\nor by mem_cgroup_iter_break()), so the memcg stays alive without it.  The\nshrinker is kept alive by the open debugfs file: shrinker_free() removes\nthe debugfs entries via debugfs_remove_recursive(), which waits for\nin-flight readers to drain, before call_rcu(..., shrinker_free_rcu_cb). \nThe sibling \"scan\" handler already invokes the sleeping ->scan_objects()\ncallback with no RCU section.\n\nDrop the rcu_read_lock()/rcu_read_unlock()."}],"providerMetadata":{"dateUpdated":"2026-07-25T08:50:58.342Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/de5f69b8dae8698ac5e48dfcd30017887cdf4e5a"},{"url":"https://git.kernel.org/stable/c/e441cbfbd0eaa6404278e985033c33caba4db767"},{"url":"https://git.kernel.org/stable/c/2fed79f0fe8c8d28a972c290dbfd693c3546c8c4"},{"url":"https://git.kernel.org/stable/c/560e21e8ccff813e84d05f6500907c549a3d6985"},{"url":"https://git.kernel.org/stable/c/86237e56091e70f09c0fbf217f9d9c0e08f556c4"},{"url":"https://git.kernel.org/stable/c/b902890c62d200b3509cb5e09cf1e0a66553c128"}],"title":"mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64419","datePublished":"2026-07-25T08:50:58.342Z","dateReserved":"2026-07-19T15:36:31.786Z","dateUpdated":"2026-07-25T08:50:58.342Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-25 10:17:25","lastModifiedDate":"2026-07-25 10:17:25","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64419","Ordinal":"1","Title":"mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show","CVE":"CVE-2026-64419","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64419","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show()\n\nReading the debugfs \"count\" file of a memcg-aware shrinker can sleep\ninside an RCU read-side critical section:\n\n  BUG: sleeping function called from invalid context at kernel/cgroup/rstat.c:421\n  RCU nest depth: 1, expected: 0\n   css_rstat_flush\n   mem_cgroup_flush_stats\n   zswap_shrinker_count\n   shrinker_debugfs_count_show\n\nshrinker_debugfs_count_show() invokes the ->count_objects() callback under\nrcu_read_lock().  The zswap callback flushes memcg stats via\ncss_rstat_flush(), which may sleep, so it must not run under RCU.\n\nThe RCU lock is not needed here.  mem_cgroup_iter() takes RCU internally\nand returns a memcg holding a css reference (dropped on the next iteration\nor by mem_cgroup_iter_break()), so the memcg stays alive without it.  The\nshrinker is kept alive by the open debugfs file: shrinker_free() removes\nthe debugfs entries via debugfs_remove_recursive(), which waits for\nin-flight readers to drain, before call_rcu(..., shrinker_free_rcu_cb). \nThe sibling \"scan\" handler already invokes the sleeping ->scan_objects()\ncallback with no RCU section.\n\nDrop the rcu_read_lock()/rcu_read_unlock().","Type":"Description","Title":"mm/shrinker: do not hold RCU lock in shrinker_debugfs_count_show"}]}}}