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FKIE_CVE-2026-72094

Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-17 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: dma-buf: dma-fence: Fix potential NULL pointer dereference The commit mentioned in the fixes tag below introduced a mechanism through which fence producers can fully decouple from fence consumers. This, desirable, mechanism is based on the fence's signaled-bit as the "decoupling point". A sophisticated interaction between RCU and atomic instructions attempts to ensure that fence consumers can still interact with fence producers through the dma_fence_ops (callback pointers into the producer). This is the desired behavior: to check for decoupling, the signaled-bit is first checked. If it's not yet signaled, RCU ensures that the ops pointer cannot yet be NULL. Hereby, dma_fence_signal_timestamp_locked() first sets the signaled-bit, and then sets the ops pointer to NULL. Readers first load the ops pointer, and then check through the signaled-bit whether the pointer can legally be accessed. These set and load operations could occur out of order on weakly ordered platforms. This problem can be solved very elegantly by using the ops pointer itself as the synchronization point. The pointer is either NULL, or cannot become NULL while it is being used thanks to RCU. Replace the signaled-bit check in dma_fence_timeline_name() and dma_fence_driver_name().
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/035219a760edb35ae9a9e96beba7f122e26a997b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/15ecfdf0ef6f6d874d0a26690d300857b39ebfd0
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dma-buf/dma-fence.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "15ecfdf0ef6f6d874d0a26690d300857b39ebfd0",
              "status": "affected",
              "version": "f4cc3ab824d6772a48ca9d9c74ac623b3309985d",
              "versionType": "git"
            },
            {
              "lessThan": "035219a760edb35ae9a9e96beba7f122e26a997b",
              "status": "affected",
              "version": "f4cc3ab824d6772a48ca9d9c74ac623b3309985d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/dma-buf/dma-fence.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndma-buf: dma-fence: Fix potential NULL pointer dereference\n\nThe commit mentioned in the fixes tag below introduced a mechanism\nthrough which fence producers can fully decouple from fence consumers.\nThis, desirable, mechanism is based on the fence\u0027s signaled-bit as the\n\"decoupling point\".\n\nA sophisticated interaction between RCU and atomic instructions attempts\nto ensure that fence consumers can still interact with fence producers\nthrough the dma_fence_ops (callback pointers into the producer).\n\nThis is the desired behavior: to check for decoupling, the signaled-bit\nis first checked. If it\u0027s not yet signaled, RCU ensures that the ops\npointer cannot yet be NULL.\n\nHereby, dma_fence_signal_timestamp_locked() first sets the signaled-bit,\nand then sets the ops pointer to NULL. Readers first load the ops\npointer, and then check through the signaled-bit whether the pointer can\nlegally be accessed.\n\nThese set and load operations could occur out of order on weakly ordered\nplatforms. This problem can be solved very elegantly by using the ops\npointer itself as the synchronization point. The pointer is either NULL,\nor cannot become NULL while it is being used thanks to RCU.\n\nReplace the signaled-bit check in dma_fence_timeline_name() and\ndma_fence_driver_name()."
    }
  ],
  "id": "CVE-2026-72094",
  "lastModified": "2026-08-17T06:18:08.327",
  "metrics": {},
  "published": "2026-08-15T06:21:23.477",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/035219a760edb35ae9a9e96beba7f122e26a997b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/15ecfdf0ef6f6d874d0a26690d300857b39ebfd0"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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