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CVE Record

CVE-2025-38515: drm/sched: Increment job count before swapping tail spsc queue

In the Linux kernel, the following vulnerability has been resolved: drm/sched: Increment job count before swapping tail spsc queue A small race exists between spsc_queue_push and the run-job worker, in which spsc_queue_push may return not-first while the run-job worker has already idled due to the job count being zero. If this race occurs, job scheduling stops, leading to hangs while waiting on the job’s DMA fences. Seal this race by incrementing the job count before appending to the SPSC queue. This race was observed on a drm-tip 6.16-rc1 build with the Xe driver in an SVM test case.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2025-38515 is a Linux kernel DRM scheduler race condition. Under specific GPU scheduling timing, jobs can stop being scheduled and systems or workloads may hang while waiting for DMA fences. The public record describes an availability problem, not data theft, remote code execution, or privilege escalation.

Executive priority

Treat this as a targeted availability risk for Linux GPU workloads, not an emergency internet-wide compromise. Patch through normal kernel maintenance, faster for systems where GPU hangs affect production, research, AI, graphics, or shared compute services.

Technical view

The race is between spsc_queue_push and the run-job worker. A push can report not-first after the worker has gone idle because job count is zero. The fix increments the job count before appending to the SPSC queue. It was observed on drm-tip 6.16-rc1 with the Xe driver in an SVM test case.

Likely exposure

Exposure appears limited to Linux systems using affected kernel versions and DRM scheduler paths, especially GPU workloads involving the Xe driver or similar DRM scheduling behavior. The source bundle does not prove broad real-world exposure across all Linux deployments.

Exploitation context

CISA KEV is false, and the provided sources do not report active exploitation. The described impact is hangs from a scheduler race, likely requiring the affected kernel code path and timing conditions rather than a straightforward remote attack.

Researcher notes

The evidence identifies a concurrency bug and stable-kernel fixes, but lacks CVSS, CWE, exploitability analysis, and detailed affected range clarity. Avoid assuming privilege escalation or remote reachability. Reproduce and validate only in controlled kernel test environments using vendor-safe procedures.

Mitigation direction

  • Apply vendor kernel updates containing the referenced stable fixes.
  • Check Linux distribution advisories, including Debian LTS notices, for packaged kernel updates.
  • Prioritize systems running affected kernels with GPU, DRM, or Xe driver workloads.
  • If patches are unavailable, monitor vendor guidance for supported mitigations or backports.

Validation and detection

  • Inventory Linux kernel versions on systems using DRM or GPU workloads.
  • Confirm whether vendor kernels include one of the referenced stable commits.
  • Review logs and workload reports for GPU hangs or DMA fence waits.
  • Track Debian LTS or distribution advisories for deployed package status.
Prepared
Confidence
medium
Sources
12

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2025-38515 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
11Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcf, 27105db6c63a571b91d01e749d026105a1e63bcfunaffected
LinuxLinux4.16, 0, 5.4.296, 5.10.240, 5.15.189, 6.1.146, 6.6.99, 6.12.39, 6.15.7, 6.16affected
Weakness

CWE details

No CWE listed

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