FKIE_CVE-2025-40329

Vulnerability from fkie_nvd - Published: 2025-12-09 16:17 - Updated: 2025-12-09 18:36
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: drm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb The Mesa issue referenced below pointed out a possible deadlock: [ 1231.611031] Possible interrupt unsafe locking scenario: [ 1231.611033] CPU0 CPU1 [ 1231.611034] ---- ---- [ 1231.611035] lock(&xa->xa_lock#17); [ 1231.611038] local_irq_disable(); [ 1231.611039] lock(&fence->lock); [ 1231.611041] lock(&xa->xa_lock#17); [ 1231.611044] <Interrupt> [ 1231.611045] lock(&fence->lock); [ 1231.611047] *** DEADLOCK *** In this example, CPU0 would be any function accessing job->dependencies through the xa_* functions that don't disable interrupts (eg: drm_sched_job_add_dependency(), drm_sched_entity_kill_jobs_cb()). CPU1 is executing drm_sched_entity_kill_jobs_cb() as a fence signalling callback so in an interrupt context. It will deadlock when trying to grab the xa_lock which is already held by CPU0. Replacing all xa_* usage by their xa_*_irq counterparts would fix this issue, but Christian pointed out another issue: dma_fence_signal takes fence.lock and so does dma_fence_add_callback. dma_fence_signal() // locks f1.lock -> drm_sched_entity_kill_jobs_cb() -> foreach dependencies -> dma_fence_add_callback() // locks f2.lock This will deadlock if f1 and f2 share the same spinlock. To fix both issues, the code iterating on dependencies and re-arming them is moved out to drm_sched_entity_kill_jobs_work(). [phasta: commit message nits]
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0d63031ee4a57be0252cb9a4e09ae921c75cece9
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3e8ada4fd838e3fd2cca94000dac054f3a347c01
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/487df8b698345dd5a91346335f05170ed5f29d4e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/70150b9443dddf02157d821c68abf438f55a2e8e
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/sched: Fix deadlock in drm_sched_entity_kill_jobs_cb\n\nThe Mesa issue referenced below pointed out a possible deadlock:\n\n[ 1231.611031]  Possible interrupt unsafe locking scenario:\n\n[ 1231.611033]        CPU0                    CPU1\n[ 1231.611034]        ----                    ----\n[ 1231.611035]   lock(\u0026xa-\u003exa_lock#17);\n[ 1231.611038]                                local_irq_disable();\n[ 1231.611039]                                lock(\u0026fence-\u003elock);\n[ 1231.611041]                                lock(\u0026xa-\u003exa_lock#17);\n[ 1231.611044]   \u003cInterrupt\u003e\n[ 1231.611045]     lock(\u0026fence-\u003elock);\n[ 1231.611047]\n                *** DEADLOCK ***\n\nIn this example, CPU0 would be any function accessing job-\u003edependencies\nthrough the xa_* functions that don\u0027t disable interrupts (eg:\ndrm_sched_job_add_dependency(), drm_sched_entity_kill_jobs_cb()).\n\nCPU1 is executing drm_sched_entity_kill_jobs_cb() as a fence signalling\ncallback so in an interrupt context. It will deadlock when trying to\ngrab the xa_lock which is already held by CPU0.\n\nReplacing all xa_* usage by their xa_*_irq counterparts would fix\nthis issue, but Christian pointed out another issue: dma_fence_signal\ntakes fence.lock and so does dma_fence_add_callback.\n\n  dma_fence_signal() // locks f1.lock\n  -\u003e drm_sched_entity_kill_jobs_cb()\n  -\u003e foreach dependencies\n     -\u003e dma_fence_add_callback() // locks f2.lock\n\nThis will deadlock if f1 and f2 share the same spinlock.\n\nTo fix both issues, the code iterating on dependencies and re-arming them\nis moved out to drm_sched_entity_kill_jobs_work().\n\n[phasta: commit message nits]"
    }
  ],
  "id": "CVE-2025-40329",
  "lastModified": "2025-12-09T18:36:53.557",
  "metrics": {},
  "published": "2025-12-09T16:17:43.017",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0d63031ee4a57be0252cb9a4e09ae921c75cece9"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e8ada4fd838e3fd2cca94000dac054f3a347c01"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/487df8b698345dd5a91346335f05170ed5f29d4e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/70150b9443dddf02157d821c68abf438f55a2e8e"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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