CVE-2025-21876 (GCVE-0-2025-21876)
Vulnerability from cvelistv5
Published
2025-03-27 14:57
Modified
2025-05-04 07:23
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix suspicious RCU usage Commit <d74169ceb0d2> ("iommu/vt-d: Allocate DMAR fault interrupts locally") moved the call to enable_drhd_fault_handling() to a code path that does not hold any lock while traversing the drhd list. Fix it by ensuring the dmar_global_lock lock is held when traversing the drhd list. Without this fix, the following warning is triggered: ============================= WARNING: suspicious RCU usage 6.14.0-rc3 #55 Not tainted ----------------------------- drivers/iommu/intel/dmar.c:2046 RCU-list traversed in non-reader section!! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 1 2 locks held by cpuhp/1/23: #0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0 #1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, at: cpuhp_thread_fun+0x87/0x2c0 stack backtrace: CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 Not tainted 6.14.0-rc3 #55 Call Trace: <TASK> dump_stack_lvl+0xb7/0xd0 lockdep_rcu_suspicious+0x159/0x1f0 ? __pfx_enable_drhd_fault_handling+0x10/0x10 enable_drhd_fault_handling+0x151/0x180 cpuhp_invoke_callback+0x1df/0x990 cpuhp_thread_fun+0x1ea/0x2c0 smpboot_thread_fn+0x1f5/0x2e0 ? __pfx_smpboot_thread_fn+0x10/0x10 kthread+0x12a/0x2d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x4a/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Holding the lock in enable_drhd_fault_handling() triggers a lockdep splat about a possible deadlock between dmar_global_lock and cpu_hotplug_lock. This is avoided by not holding dmar_global_lock when calling iommu_device_register(), which initiates the device probe process.
References
Impacted products
Vendor Product Version
Linux Linux Version: d74169ceb0d2e32438946a2f1f9fc8c803304bd6
Version: d74169ceb0d2e32438946a2f1f9fc8c803304bd6
Version: d74169ceb0d2e32438946a2f1f9fc8c803304bd6
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iommu/intel/dmar.c",
            "drivers/iommu/intel/iommu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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            "drivers/iommu/intel/dmar.c",
            "drivers/iommu/intel/iommu.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.12.18",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.13.*",
              "status": "unaffected",
              "version": "6.13.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.14",
              "versionType": "original_commit_for_fix"
            }
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        }
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niommu/vt-d: Fix suspicious RCU usage\n\nCommit \u003cd74169ceb0d2\u003e (\"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  \u003cTASK\u003e\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  \u003c/TASK\u003e\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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-04T07:23:02.780Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/4117c72938493a77ab53cc4b8284be8fb6ec8065"
        },
        {
          "url": "https://git.kernel.org/stable/c/c603ccbe91d189849e1439134598ec567088dcec"
        },
        {
          "url": "https://git.kernel.org/stable/c/b150654f74bf0df8e6a7936d5ec51400d9ec06d8"
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      ],
      "title": "iommu/vt-d: Fix suspicious RCU usage",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-21876",
    "datePublished": "2025-03-27T14:57:06.802Z",
    "dateReserved": "2024-12-29T08:45:45.781Z",
    "dateUpdated": "2025-05-04T07:23:02.780Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-21876\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-03-27T15:15:55.430\",\"lastModified\":\"2025-10-30T16:00:56.877\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\niommu/vt-d: Fix suspicious RCU usage\\n\\nCommit \u003cd74169ceb0d2\u003e (\\\"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  \u003cTASK\u003e\\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  \u003c/TASK\u003e\\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.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: iommu/vt-d: Correcci\u00f3n de uso sospechoso de RCU. El commit  (\\\"iommu/vt-d: Asignar interrupciones de fallo DMAR localmente\\\") movi\u00f3 la llamada a enable_drhd_fault_handling() a una ruta de c\u00f3digo que no mantiene ning\u00fan bloqueo al recorrer la lista drhd. Corr\u00edjala asegur\u00e1ndose de que el bloqueo dmar_global_lock se mantenga al recorrer la lista drhd. Sin esta correcci\u00f3n, se activa la siguiente advertencia: ============================= ADVERTENCIA: uso sospechoso de RCU 6.14.0-rc3 #55 No contaminado ----------------------------- drivers/iommu/intel/dmar.c:2046 \u00a1Lista de RCU recorrida en una secci\u00f3n que no es de lectura! Otra informaci\u00f3n que podr\u00eda ayudarnos a depurar esto: rcu_scheduler_active = 1, debug_locks = 1 2 bloqueos mantenidos por cpuhp/1/23: #0: ffffffff84a67c50 (cpu_hotplug_lock){++++}-{0:0}, en: cpuhp_thread_fun+0x87/0x2c0 #1: ffffffff84a6a380 (cpuhp_state-up){+.+.}-{0:0}, en: cpuhp_thread_fun+0x87/0x2c0 seguimiento de pila: CPU: 1 UID: 0 PID: 23 Comm: cpuhp/1 No contaminado 6.14.0-rc3 #55 Seguimiento de llamadas:   dump_stack_lvl+0xb7/0xd0 lockdep_rcu_suspicious+0x159/0x1f0 ? __pfx_enable_drhd_fault_handling+0x10/0x10 enable_drhd_fault_handling+0x151/0x180 cpuhp_invoke_callback+0x1df/0x990 cpuhp_thread_fun+0x1ea/0x2c0 smpboot_thread_fn+0x1f5/0x2e0 ? __pfx_smpboot_thread_fn+0x10/0x10 kthread+0x12a/0x2d0 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x4a/0x60 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30  Mantener el bloqueo en enable_drhd_fault_handling() activa un aviso de bloqueo sobre un posible interbloqueo entre dmar_global_lock y cpu_hotplug_lock. Esto se evita al no mantener dmar_global_lock al llamar a iommu_device_register(), que inicia el proceso de sondeo del dispositivo.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"NVD-CWE-noinfo\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.10\",\"versionEndExcluding\":\"6.12.18\",\"matchCriteriaId\":\"C3E726AB-924C-4BAA-9AD5-2EA4A154FEE8\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.13\",\"versionEndExcluding\":\"6.13.6\",\"matchCriteriaId\":\"64F12D9B-71C2-4CD7-A288-0D5EF1709620\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"186716B6-2B66-4BD0-852E-D48E71C0C85F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"0D3E781C-403A-498F-9DA9-ECEE50F41E75\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"66619FB8-0AAF-4166-B2CF-67B24143261D\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"D3D6550E-6679-4560-902D-AF52DCFE905B\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/4117c72938493a77ab53cc4b8284be8fb6ec8065\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/b150654f74bf0df8e6a7936d5ec51400d9ec06d8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/c603ccbe91d189849e1439134598ec567088dcec\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}"
  }
}


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