{"id":"CVE-2025-21876","revision":"5ad62cb432664f9daae7437379bcc55a","records":[{"revision":"5ad62cb432664f9daae7437379bcc55a","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2025-21876","aliases":[],"title":"iommu/vt-d: Fix suspicious RCU usage","description":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Fix suspicious RCU usage\n\nCommit <d74169ceb0d2> (\"iommu/vt-d: Allocate DMAR fault interrupts\nlocally\") moved the call to enable_drhd_fault_handling() to a code\npath that does not hold any lock while traversing the drhd list. Fix\nit by ensuring the dmar_global_lock lock is held when traversing the\ndrhd list.\n\nWithout this fix, the following warning is triggered:\n =============================\n WARNING: suspicious RCU usage\n 6.14.0-rc3 #55 Not tainted\n -----------------------------\n drivers/iommu/intel/dmar.c:2046 RCU-list traversed in non-reader section!!\n               other info that might help us debug this:\n               rcu_scheduler_active = 1, debug_locks = 1\n 2 locks held by cpuhp/1/23:\n #0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0\n #1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0\n stack backtrace:\n CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 Not tainted 6.14.0-rc3 #55\n Call Trace:\n  <TASK>\n  dump_stack_lvl+0xb7/0xd0\n  lockdep_rcu_suspicious+0x159/0x1f0\n  ? __pfx_enable_drhd_fault_handling+0x10/0x10\n  enable_drhd_fault_handling+0x151/0x180\n  cpuhp_invoke_callback+0x1df/0x990\n  cpuhp_thread_fun+0x1ea/0x2c0\n  smpboot_thread_fn+0x1f5/0x2e0\n  ? __pfx_smpboot_thread_fn+0x10/0x10\n  kthread+0x12a/0x2d0\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork+0x4a/0x60\n  ? __pfx_kthread+0x10/0x10\n  ret_from_fork_asm+0x1a/0x30\n  </TASK>\n\nHolding the lock in enable_drhd_fault_handling() triggers a lockdep splat\nabout a possible deadlock between dmar_global_lock and cpu_hotplug_lock.\nThis is avoided by not holding dmar_global_lock when calling\niommu_device_register(), which initiates the device probe process.","state":0,"publishedAt":"2025-03-27T14:57:06.802+00:00","modifiedAt":"2026-10-15T21:51:54.56+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/iommu/intel/dmar.c\",\n                        \"drivers/iommu/intel/iommu.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"d74169ceb0d2e32438946a2f1f9fc8c803304bd6\",\n                            \"lessThan\": \"4117c72938493a77ab53cc4b8284be8fb6ec8065\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d74169ceb0d2e32438946a2f1f9fc8c803304bd6\",\n                            \"lessThan\": \"c603ccbe91d189849e1439134598ec567088dcec\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"d74169ceb0d2e32438946a2f1f9fc8c803304bd6\",\n                            \"lessThan\": \"b150654f74bf0df8e6a7936d5ec51400d9ec06d8\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"drivers/iommu/intel/dmar.c\",\n                        \"drivers/iommu/intel/iommu.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"6.10\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"6.10\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.18\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.13.6\",\n                            \"lessThanOrEqual\": \"6.13.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.14\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":8.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/4117c72938493a77ab53cc4b8284be8fb6ec8065","https://git.kernel.org/stable/c/c603ccbe91d189849e1439134598ec567088dcec","https://git.kernel.org/stable/c/b150654f74bf0df8e6a7936d5ec51400d9ec06d8"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-21876","license":"CVE Program Terms of Use","key":"cve-program:CVE-2025-21876","identifiers":["CVE-2025-21876"]},"retained":false,"historicalAffected":[]}],"coverage":[]}