{"id":"CVE-2025-21983","state":"PUBLISHED","title":"mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq\n\nCurrently kvfree_rcu() APIs use a system workqueue which is\n\"system_unbound_wq\" to driver RCU machinery to reclaim a memory.\n\nRecently, it has been noted that the following kernel warning can\nbe observed:\n\n<snip>\nworkqueue: WQ_MEM_RECLAIM nvme-wq:nvme_scan_work is flushing !WQ_MEM_RECLAIM events_unbound:kfree_rcu_work\n  WARNING: CPU: 21 PID: 330 at kernel/workqueue.c:3719 check_flush_dependency+0x112/0x120\n  Modules linked in: intel_uncore_frequency(E) intel_uncore_frequency_common(E) skx_edac(E) ...\n  CPU: 21 UID: 0 PID: 330 Comm: kworker/u144:6 Tainted: G            E      6.13.2-0_g925d379822da #1\n  Hardware name: Wiwynn Twin Lakes MP/Twin Lakes Passive MP, BIOS YMM20 02/01/2023\n  Workqueue: nvme-wq nvme_scan_work\n  RIP: 0010:check_flush_dependency+0x112/0x120\n  Code: 05 9a 40 14 02 01 48 81 c6 c0 00 00 00 48 8b 50 18 48 81 c7 c0 00 00 00 48 89 f9 48 ...\n  RSP: 0018:ffffc90000df7bd8 EFLAGS: 00010082\n  RAX: 000000000000006a RBX: ffffffff81622390 RCX: 0000000000000027\n  RDX: 00000000fffeffff RSI: 000000000057ffa8 RDI: ffff88907f960c88\n  RBP: 0000000000000000 R08: ffffffff83068e50 R09: 000000000002fffd\n  R10: 0000000000000004 R11: 0000000000000000 R12: ffff8881001a4400\n  R13: 0000000000000000 R14: ffff88907f420fb8 R15: 0000000000000000\n  FS:  0000000000000000(0000) GS:ffff88907f940000(0000) knlGS:0000000000000000\n  CR2: 00007f60c3001000 CR3: 000000107d010005 CR4: 00000000007726f0\n  PKRU: 55555554\n  Call Trace:\n   <TASK>\n   ? __warn+0xa4/0x140\n   ? check_flush_dependency+0x112/0x120\n   ? report_bug+0xe1/0x140\n   ? check_flush_dependency+0x112/0x120\n   ? handle_bug+0x5e/0x90\n   ? exc_invalid_op+0x16/0x40\n   ? asm_exc_invalid_op+0x16/0x20\n   ? timer_recalc_next_expiry+0x190/0x190\n   ? check_flush_dependency+0x112/0x120\n   ? check_flush_dependency+0x112/0x120\n   __flush_work.llvm.1643880146586177030+0x174/0x2c0\n   flush_rcu_work+0x28/0x30\n   kvfree_rcu_barrier+0x12f/0x160\n   kmem_cache_destroy+0x18/0x120\n   bioset_exit+0x10c/0x150\n   disk_release.llvm.6740012984264378178+0x61/0xd0\n   device_release+0x4f/0x90\n   kobject_put+0x95/0x180\n   nvme_put_ns+0x23/0xc0\n   nvme_remove_invalid_namespaces+0xb3/0xd0\n   nvme_scan_work+0x342/0x490\n   process_scheduled_works+0x1a2/0x370\n   worker_thread+0x2ff/0x390\n   ? pwq_release_workfn+0x1e0/0x1e0\n   kthread+0xb1/0xe0\n   ? __kthread_parkme+0x70/0x70\n   ret_from_fork+0x30/0x40\n   ? __kthread_parkme+0x70/0x70\n   ret_from_fork_asm+0x11/0x20\n   </TASK>\n  ---[ end trace 0000000000000000 ]---\n<snip>\n\nTo address this switch to use of independent WQ_MEM_RECLAIM\nworkqueue, so the rules are not violated from workqueue framework\npoint of view.\n\nApart of that, since kvfree_rcu() does reclaim memory it is worth\nto go with WQ_MEM_RECLAIM type of wq because it is designed for\nthis purpose.","publishedAt":"2025-04-01T15:47:10.949Z","updatedAt":"2026-05-11T21:10:22.288Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"a74979dce9e9c61f6d797c3761020252c4d8dc63","versionType":"git"},{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"656e35bf66a11e1adde44c4c12050086dc39f241","versionType":"git"},{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"dfd3df31c9db752234d7d2e09bef2aeabb643ce4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/slab_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.20","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.8","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/slab_common.c"]}],"references":["https://git.kernel.org/stable/c/a74979dce9e9c61f6d797c3761020252c4d8dc63","https://git.kernel.org/stable/c/656e35bf66a11e1adde44c4c12050086dc39f241","https://git.kernel.org/stable/c/dfd3df31c9db752234d7d2e09bef2aeabb643ce4"],"weaknesses":[],"ingestedAt":"2026-10-29T20:08:39.238Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/21xxx/CVE-2025-21983.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21983","state":"PUBLISHED","datePublished":"2025-04-01T15:47:10.949Z","dateUpdated":"2026-05-11T21:10:22.288Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-12-29T08:45:45.799Z"},"containers":{"cna":{"title":"mm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/slab/kvfree_rcu: Switch to WQ_MEM_RECLAIM wq\n\nCurrently kvfree_rcu() APIs use a system workqueue which is\n\"system_unbound_wq\" to driver RCU machinery to reclaim a memory.\n\nRecently, it has been noted that the following kernel warning can\nbe observed:\n\n<snip>\nworkqueue: WQ_MEM_RECLAIM nvme-wq:nvme_scan_work is flushing !WQ_MEM_RECLAIM events_unbound:kfree_rcu_work\n  WARNING: CPU: 21 PID: 330 at kernel/workqueue.c:3719 check_flush_dependency+0x112/0x120\n  Modules linked in: intel_uncore_frequency(E) intel_uncore_frequency_common(E) skx_edac(E) ...\n  CPU: 21 UID: 0 PID: 330 Comm: kworker/u144:6 Tainted: G            E      6.13.2-0_g925d379822da #1\n  Hardware name: Wiwynn Twin Lakes MP/Twin Lakes Passive MP, BIOS YMM20 02/01/2023\n  Workqueue: nvme-wq nvme_scan_work\n  RIP: 0010:check_flush_dependency+0x112/0x120\n  Code: 05 9a 40 14 02 01 48 81 c6 c0 00 00 00 48 8b 50 18 48 81 c7 c0 00 00 00 48 89 f9 48 ...\n  RSP: 0018:ffffc90000df7bd8 EFLAGS: 00010082\n  RAX: 000000000000006a RBX: ffffffff81622390 RCX: 0000000000000027\n  RDX: 00000000fffeffff RSI: 000000000057ffa8 RDI: ffff88907f960c88\n  RBP: 0000000000000000 R08: ffffffff83068e50 R09: 000000000002fffd\n  R10: 0000000000000004 R11: 0000000000000000 R12: ffff8881001a4400\n  R13: 0000000000000000 R14: ffff88907f420fb8 R15: 0000000000000000\n  FS:  0000000000000000(0000) GS:ffff88907f940000(0000) knlGS:0000000000000000\n  CR2: 00007f60c3001000 CR3: 000000107d010005 CR4: 00000000007726f0\n  PKRU: 55555554\n  Call Trace:\n   <TASK>\n   ? __warn+0xa4/0x140\n   ? check_flush_dependency+0x112/0x120\n   ? report_bug+0xe1/0x140\n   ? check_flush_dependency+0x112/0x120\n   ? handle_bug+0x5e/0x90\n   ? exc_invalid_op+0x16/0x40\n   ? asm_exc_invalid_op+0x16/0x20\n   ? timer_recalc_next_expiry+0x190/0x190\n   ? check_flush_dependency+0x112/0x120\n   ? check_flush_dependency+0x112/0x120\n   __flush_work.llvm.1643880146586177030+0x174/0x2c0\n   flush_rcu_work+0x28/0x30\n   kvfree_rcu_barrier+0x12f/0x160\n   kmem_cache_destroy+0x18/0x120\n   bioset_exit+0x10c/0x150\n   disk_release.llvm.6740012984264378178+0x61/0xd0\n   device_release+0x4f/0x90\n   kobject_put+0x95/0x180\n   nvme_put_ns+0x23/0xc0\n   nvme_remove_invalid_namespaces+0xb3/0xd0\n   nvme_scan_work+0x342/0x490\n   process_scheduled_works+0x1a2/0x370\n   worker_thread+0x2ff/0x390\n   ? pwq_release_workfn+0x1e0/0x1e0\n   kthread+0xb1/0xe0\n   ? __kthread_parkme+0x70/0x70\n   ret_from_fork+0x30/0x40\n   ? __kthread_parkme+0x70/0x70\n   ret_from_fork_asm+0x11/0x20\n   </TASK>\n  ---[ end trace 0000000000000000 ]---\n<snip>\n\nTo address this switch to use of independent WQ_MEM_RECLAIM\nworkqueue, so the rules are not violated from workqueue framework\npoint of view.\n\nApart of that, since kvfree_rcu() does reclaim memory it is worth\nto go with WQ_MEM_RECLAIM type of wq because it is designed for\nthis purpose."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"a74979dce9e9c61f6d797c3761020252c4d8dc63","versionType":"git"},{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"656e35bf66a11e1adde44c4c12050086dc39f241","versionType":"git"},{"version":"6c6c47b063b593785202be158e61fe5c827d6677","status":"affected","lessThan":"dfd3df31c9db752234d7d2e09bef2aeabb643ce4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/slab_common.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.12.20","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13.8","status":"unaffected","lessThanOrEqual":"6.13.*","versionType":"semver"},{"version":"6.14","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/slab_common.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/a74979dce9e9c61f6d797c3761020252c4d8dc63"},{"url":"https://git.kernel.org/stable/c/656e35bf66a11e1adde44c4c12050086dc39f241"},{"url":"https://git.kernel.org/stable/c/dfd3df31c9db752234d7d2e09bef2aeabb643ce4"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:10:22.288Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.12.20"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.13.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12","versionEndExcluding":"6.14"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}