FKIE_CVE-2025-68209

Vulnerability from fkie_nvd - Published: 2025-12-16 14:15 - Updated: 2025-12-18 15:08
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: mlx5: Fix default values in create CQ Currently, CQs without a completion function are assigned the mlx5_add_cq_to_tasklet function by default. This is problematic since only user CQs created through the mlx5_ib driver are intended to use this function. Additionally, all CQs that will use doorbells instead of polling for completions must call mlx5_cq_arm. However, the default CQ creation flow leaves a valid value in the CQ's arm_db field, allowing FW to send interrupts to polling-only CQs in certain corner cases. These two factors would allow a polling-only kernel CQ to be triggered by an EQ interrupt and call a completion function intended only for user CQs, causing a null pointer exception. Some areas in the driver have prevented this issue with one-off fixes but did not address the root cause. This patch fixes the described issue by adding defaults to the create CQ flow. It adds a default dummy completion function to protect against null pointer exceptions, and it sets an invalid command sequence number by default in kernel CQs to prevent the FW from sending an interrupt to the CQ until it is armed. User CQs are responsible for their own initialization values. Callers of mlx5_core_create_cq are responsible for changing the completion function and arming the CQ per their needs.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/08469f5393a1a39f26a6e2eb2e8c33187665c1f4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e5eba42f01340f73888dfe560be2806057c25913
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmlx5: Fix default values in create CQ\n\nCurrently, CQs without a completion function are assigned the\nmlx5_add_cq_to_tasklet function by default. This is problematic since\nonly user CQs created through the mlx5_ib driver are intended to use\nthis function.\n\nAdditionally, all CQs that will use doorbells instead of polling for\ncompletions must call mlx5_cq_arm. However, the default CQ creation flow\nleaves a valid value in the CQ\u0027s arm_db field, allowing FW to send\ninterrupts to polling-only CQs in certain corner cases.\n\nThese two factors would allow a polling-only kernel CQ to be triggered\nby an EQ interrupt and call a completion function intended only for user\nCQs, causing a null pointer exception.\n\nSome areas in the driver have prevented this issue with one-off fixes\nbut did not address the root cause.\n\nThis patch fixes the described issue by adding defaults to the create CQ\nflow. It adds a default dummy completion function to protect against\nnull pointer exceptions, and it sets an invalid command sequence number\nby default in kernel CQs to prevent the FW from sending an interrupt to\nthe CQ until it is armed. User CQs are responsible for their own\ninitialization values.\n\nCallers of mlx5_core_create_cq are responsible for changing the\ncompletion function and arming the CQ per their needs."
    }
  ],
  "id": "CVE-2025-68209",
  "lastModified": "2025-12-18T15:08:25.907",
  "metrics": {},
  "published": "2025-12-16T14:15:53.813",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/08469f5393a1a39f26a6e2eb2e8c33187665c1f4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e5eba42f01340f73888dfe560be2806057c25913"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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