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GHSA-97PV-PQPM-W4FG

Vulnerability from github – Published: 2026-09-09 18:32 – Updated: 2026-09-09 18:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: fix recursive ww_mutex acquire in amdgpu_devcoredump_format

When dumping IB contents from a hung job, amdgpu_devcoredump_format() acquired the VM root PD's reservation via amdgpu_vm_lock_by_pasid() and then, for each IB, called amdgpu_bo_reserve() on the BO backing the IB. Both reservations are reservation_ww_class_mutex objects and neither used a ww_acquire_ctx, which trips lockdep:

WARNING: possible recursive locking detected


kworker/u128:0 is trying to acquire lock: ffff88838b16e1f0 (reservation_ww_class_mutex){+.+.}-{4:4}, at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu]

but task is already holding lock: ffff8882f82681f0 (reservation_ww_class_mutex){+.+.}-{4:4}, at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu]

Possible unsafe locking scenario: CPU0 ---- lock(reservation_ww_class_mutex); lock(reservation_ww_class_mutex);

*** DEADLOCK *** May be due to missing lock nesting notation

Workqueue: events_unbound amdgpu_devcoredump_deferred_work [amdgpu] Call Trace: __ww_mutex_lock.constprop.0 ww_mutex_lock amdgpu_bo_reserve amdgpu_devcoredump_format+0x1594 [amdgpu] amdgpu_devcoredump_deferred_work+0xea [amdgpu]

The two reservations are on different BOs in the captured trace, so the splat is a lockdep-correctness warning, not an observed deadlock. It becomes a real self-deadlock whenever the IB BO shares its dma_resv with the root PD (the always-valid case, see amdgpu_vm_is_bo_always_valid()): amdgpu_bo_reserve(abo) re-acquires the same ww_mutex without a ticket and blocks forever. With amdgpu.gpu_recovery=0 the timeout handler refires every ~2 s and each invocation produces this splat, drowning the kernel ring buffer.

Now that amdgpu_vm_lock_by_pasid() takes a drm_exec context, move the IB dumping into a separate helper that locks the root PD and every IB BO together in a single drm_exec ticket. DRM_EXEC_IGNORE_DUPLICATES handles IB BOs that share a dma_resv (e.g. always-valid BOs, or two IBs backed by the same BO). Every lock is now a top-level acquire under one ww_acquire_ctx, so the recursive ww_mutex condition is gone, and the per-IB amdgpu_bo_reserve()/amdgpu_bo_unref() dance -- including a BO refcount leak on the amdgpu_bo_reserve() failure path -- is removed.

(cherry picked from commit d6bf4242731219ee08ce54c365631e395486651e)

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2026-80919"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-09T17:17:47Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amdgpu: fix recursive ww_mutex acquire in amdgpu_devcoredump_format\n\nWhen dumping IB contents from a hung job, amdgpu_devcoredump_format()\nacquired the VM root PD\u0027s reservation via amdgpu_vm_lock_by_pasid() and\nthen, for each IB, called amdgpu_bo_reserve() on the BO backing the IB.\nBoth reservations are reservation_ww_class_mutex objects and neither\nused a ww_acquire_ctx, which trips lockdep:\n\n  WARNING: possible recursive locking detected\n  --------------------------------------------\n  kworker/u128:0 is trying to acquire lock:\n  ffff88838b16e1f0 (reservation_ww_class_mutex){+.+.}-{4:4},\n    at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu]\n\n  but task is already holding lock:\n  ffff8882f82681f0 (reservation_ww_class_mutex){+.+.}-{4:4},\n    at: amdgpu_devcoredump_format+0x1594/0x23f0 [amdgpu]\n\n   Possible unsafe locking scenario:\n         CPU0\n         ----\n    lock(reservation_ww_class_mutex);\n    lock(reservation_ww_class_mutex);\n\n   *** DEADLOCK ***\n   May be due to missing lock nesting notation\n\n  Workqueue: events_unbound amdgpu_devcoredump_deferred_work [amdgpu]\n  Call Trace:\n   __ww_mutex_lock.constprop.0\n   ww_mutex_lock\n   amdgpu_bo_reserve\n   amdgpu_devcoredump_format+0x1594 [amdgpu]\n   amdgpu_devcoredump_deferred_work+0xea [amdgpu]\n\nThe two reservations are on different BOs in the captured trace, so the\nsplat is a lockdep-correctness warning, not an observed deadlock. It\nbecomes a real self-deadlock whenever the IB BO shares its dma_resv with\nthe root PD (the always-valid case, see amdgpu_vm_is_bo_always_valid()):\namdgpu_bo_reserve(abo) re-acquires the same ww_mutex without a ticket\nand blocks forever. With amdgpu.gpu_recovery=0 the timeout handler\nrefires every ~2 s and each invocation produces this splat, drowning the\nkernel ring buffer.\n\nNow that amdgpu_vm_lock_by_pasid() takes a drm_exec context, move the IB\ndumping into a separate helper that locks the root PD and every IB BO\ntogether in a single drm_exec ticket. DRM_EXEC_IGNORE_DUPLICATES handles\nIB BOs that share a dma_resv (e.g. always-valid BOs, or two IBs backed\nby the same BO). Every lock is now a top-level acquire under one\nww_acquire_ctx, so the recursive ww_mutex condition is gone, and the\nper-IB amdgpu_bo_reserve()/amdgpu_bo_unref() dance -- including a BO\nrefcount leak on the amdgpu_bo_reserve() failure path -- is removed.\n\n(cherry picked from commit d6bf4242731219ee08ce54c365631e395486651e)",
  "id": "GHSA-97pv-pqpm-w4fg",
  "modified": "2026-09-09T18:32:04Z",
  "published": "2026-09-09T18:32:04Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80919"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4e9b4dee0777ec9c835a4746e2d30382dd9d1044"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7152b248dc3c8d5fa8629e99ed5655dd41b51562"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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