{"id":"CVE-2025-21886","state":"PUBLISHED","title":"RDMA/mlx5: Fix implicit ODP hang on parent deregistration","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix implicit ODP hang on parent deregistration\n\nFix the destroy_unused_implicit_child_mr() to prevent hanging during\nparent deregistration as of below [1].\n\nUpon entering destroy_unused_implicit_child_mr(), the reference count\nfor the implicit MR parent is incremented using:\nrefcount_inc_not_zero().\n\nA corresponding decrement must be performed if\nfree_implicit_child_mr_work() is not called.\n\nThe code has been updated to properly manage the reference count that\nwas incremented.\n\n[1]\nINFO: task python3:2157 blocked for more than 120 seconds.\nNot tainted 6.12.0-rc7+ #1633\n\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\ntask:python3         state:D stack:0     pid:2157 tgid:2157  ppid:1685   flags:0x00000000\nCall Trace:\n<TASK>\n__schedule+0x420/0xd30\nschedule+0x47/0x130\n__mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib]\n? __pfx_autoremove_wake_function+0x10/0x10\nib_dereg_mr_user+0x5f/0x120 [ib_core]\n? lock_release+0xc6/0x280\ndestroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs]\nuverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs]\nuobj_destroy+0x3f/0x70 [ib_uverbs]\nib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs]\n? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs]\n? lock_acquire+0xc1/0x2f0\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs]\n? lock_release+0xc6/0x280\nib_uverbs_ioctl+0xe7/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n __x64_sys_ioctl+0x1b0/0xa70\n? kmem_cache_free+0x221/0x400\ndo_syscall_64+0x6b/0x140\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7f20f21f017b\nRSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b\nRDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003\nRBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60\nR10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890\nR13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0\n</TASK>","publishedAt":"2025-03-27T14:57:13.923Z","updatedAt":"2026-10-30T12:20:56.440Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"032f3f799fdb807a21467b7dc7d620395a735e2b","status":"affected","lessThan":"641e50b27e87d7cd0d194f7a164703de599055b1","versionType":"git"},{"version":"7cc8f681f6d4ae4478ae0f60485fc768f2b450da","status":"affected","lessThan":"cb96ae783e7249e8e5a50c22952c0bb2983133df","versionType":"git"},{"version":"edfb65dbb9ffd3102f3ff4dd21316158e56f1976","status":"affected","lessThan":"a095ede2daca49d15e74d66d014883f2fa8bb924","versionType":"git"},{"version":"d3d930411ce390e532470194296658a960887773","status":"affected","lessThan":"3d8c6f26893d55fab218ad086719de1fc9bb86ba","versionType":"git"},{"version":"a306dfff6b76aafa264ad33874a8992a8d5858b7","status":"affected","versionType":"git"},{"version":"6.6.160","status":"affected","lessThan":"6.7","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/hw/mlx5/odp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.12.13","status":"affected","lessThan":"6.12.18","versionType":"semver"},{"version":"6.13.2","status":"affected","lessThan":"6.13.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/hw/mlx5/odp.c"]}],"references":["https://git.kernel.org/stable/c/641e50b27e87d7cd0d194f7a164703de599055b1","https://git.kernel.org/stable/c/cb96ae783e7249e8e5a50c22952c0bb2983133df","https://git.kernel.org/stable/c/a095ede2daca49d15e74d66d014883f2fa8bb924","https://git.kernel.org/stable/c/3d8c6f26893d55fab218ad086719de1fc9bb86ba"],"weaknesses":[],"ingestedAt":"2026-10-30T12:38:04.623Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/21xxx/CVE-2025-21886.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-21886","state":"PUBLISHED","datePublished":"2025-03-27T14:57:13.923Z","dateUpdated":"2026-10-30T12:20:56.440Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-12-29T08:45:45.782Z"},"containers":{"cna":{"title":"RDMA/mlx5: Fix implicit ODP hang on parent deregistration","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix implicit ODP hang on parent deregistration\n\nFix the destroy_unused_implicit_child_mr() to prevent hanging during\nparent deregistration as of below [1].\n\nUpon entering destroy_unused_implicit_child_mr(), the reference count\nfor the implicit MR parent is incremented using:\nrefcount_inc_not_zero().\n\nA corresponding decrement must be performed if\nfree_implicit_child_mr_work() is not called.\n\nThe code has been updated to properly manage the reference count that\nwas incremented.\n\n[1]\nINFO: task python3:2157 blocked for more than 120 seconds.\nNot tainted 6.12.0-rc7+ #1633\n\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\" disables this message.\ntask:python3         state:D stack:0     pid:2157 tgid:2157  ppid:1685   flags:0x00000000\nCall Trace:\n<TASK>\n__schedule+0x420/0xd30\nschedule+0x47/0x130\n__mlx5_ib_dereg_mr+0x379/0x5d0 [mlx5_ib]\n? __pfx_autoremove_wake_function+0x10/0x10\nib_dereg_mr_user+0x5f/0x120 [ib_core]\n? lock_release+0xc6/0x280\ndestroy_hw_idr_uobject+0x1d/0x60 [ib_uverbs]\nuverbs_destroy_uobject+0x58/0x1d0 [ib_uverbs]\nuobj_destroy+0x3f/0x70 [ib_uverbs]\nib_uverbs_cmd_verbs+0x3e4/0xbb0 [ib_uverbs]\n? __pfx_uverbs_destroy_def_handler+0x10/0x10 [ib_uverbs]\n? lock_acquire+0xc1/0x2f0\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0x116/0x170 [ib_uverbs]\n? lock_release+0xc6/0x280\nib_uverbs_ioctl+0xe7/0x170 [ib_uverbs]\n? ib_uverbs_ioctl+0xcb/0x170 [ib_uverbs]\n __x64_sys_ioctl+0x1b0/0xa70\n? kmem_cache_free+0x221/0x400\ndo_syscall_64+0x6b/0x140\nentry_SYSCALL_64_after_hwframe+0x76/0x7e\nRIP: 0033:0x7f20f21f017b\nRSP: 002b:00007ffcfc4a77c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 00007ffcfc4a78d8 RCX: 00007f20f21f017b\nRDX: 00007ffcfc4a78c0 RSI: 00000000c0181b01 RDI: 0000000000000003\nRBP: 00007ffcfc4a78a0 R08: 000056147d125190 R09: 00007f20f1f14c60\nR10: 0000000000000001 R11: 0000000000000246 R12: 00007ffcfc4a7890\nR13: 000000000000001c R14: 000056147d100fc0 R15: 00007f20e365c9d0\n</TASK>"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"032f3f799fdb807a21467b7dc7d620395a735e2b","status":"affected","lessThan":"641e50b27e87d7cd0d194f7a164703de599055b1","versionType":"git"},{"version":"7cc8f681f6d4ae4478ae0f60485fc768f2b450da","status":"affected","lessThan":"cb96ae783e7249e8e5a50c22952c0bb2983133df","versionType":"git"},{"version":"edfb65dbb9ffd3102f3ff4dd21316158e56f1976","status":"affected","lessThan":"a095ede2daca49d15e74d66d014883f2fa8bb924","versionType":"git"},{"version":"d3d930411ce390e532470194296658a960887773","status":"affected","lessThan":"3d8c6f26893d55fab218ad086719de1fc9bb86ba","versionType":"git"},{"version":"a306dfff6b76aafa264ad33874a8992a8d5858b7","status":"affected","versionType":"git"},{"version":"6.6.160","status":"affected","lessThan":"6.7","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/hw/mlx5/odp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.12.13","status":"affected","lessThan":"6.12.18","versionType":"semver"},{"version":"6.13.2","status":"affected","lessThan":"6.13.6","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/infiniband/hw/mlx5/odp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/641e50b27e87d7cd0d194f7a164703de599055b1"},{"url":"https://git.kernel.org/stable/c/cb96ae783e7249e8e5a50c22952c0bb2983133df"},{"url":"https://git.kernel.org/stable/c/a095ede2daca49d15e74d66d014883f2fa8bb924"},{"url":"https://git.kernel.org/stable/c/3d8c6f26893d55fab218ad086719de1fc9bb86ba"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:20:56.440Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.13","versionEndExcluding":"6.12.18"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13.2","versionEndExcluding":"6.13.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.160"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}