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CVE Record

CVE-2024-35991: dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: Convert spinlock to mutex to lock evl workqueue drain_workqueue() cannot be called safely in a spinlocked context due to possible task rescheduling. In the multi-task scenario, calling queue_work() while drain_workqueue() will lead to a Call Trace as pushing a work on a draining workqueue is not permitted in spinlocked context. Call Trace: <TASK> ? __warn+0x7d/0x140 ? __queue_work+0x2b2/0x440 ? report_bug+0x1f8/0x200 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x18/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? __queue_work+0x2b2/0x440 queue_work_on+0x28/0x30 idxd_misc_thread+0x303/0x5a0 [idxd] ? __schedule+0x369/0xb40 ? __pfx_irq_thread_fn+0x10/0x10 ? irq_thread+0xbc/0x1b0 irq_thread_fn+0x21/0x70 irq_thread+0x102/0x1b0 ? preempt_count_add+0x74/0xa0 ? __pfx_irq_thread_dtor+0x10/0x10 ? __pfx_irq_thread+0x10/0x10 kthread+0x103/0x140 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x31/0x50 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1b/0x30 </TASK> The current implementation uses a spinlock to protect event log workqueue and will lead to the Call Trace due to potential task rescheduling. To address the locking issue, convert the spinlock to mutex, allowing the drain_workqueue() to be called in a safe mutex-locked context. This change ensures proper synchronization when accessing the event log workqueue, preventing potential Call Trace and improving the overall robustness of the code.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2024-35991 is a Linux kernel reliability flaw in the idxd DMA engine driver. A locking mistake can allow unsafe workqueue draining and trigger a kernel call trace. The source bundle describes a kernel fix, but gives no CVSS score, CWE, or confirmed real-world exploitation.

Executive priority

Treat this as a kernel maintenance and reliability issue unless local evidence shows repeated crashes or warnings. There is no source-backed evidence of active exploitation, but exposed systems using idxd should receive timely kernel updates.

Technical view

The idxd driver protected event log workqueue access with a spinlock while calling drain_workqueue(), which can reschedule and is unsafe in spinlocked context. Concurrent queue_work() during draining can trigger a warning call trace. The fix converts that lock to a mutex so workqueue draining occurs in a sleepable context.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds with the dmaengine idxd driver path present or in use. The bundle lists Linux 6.4, 6.6.30, 6.8.9, and 6.9 as affected, but distro backport status is not provided.

Exploitation context

No active exploitation is supported by the bundle. The CVE is not listed as KEV, and the description frames the issue as a synchronization bug causing a call trace rather than a documented attacker technique.

Researcher notes

The available evidence supports a concurrency defect in the Linux idxd driver workqueue locking model. Impact details are incomplete: no CVSS, CWE, exploitability analysis, privilege requirement, or distro-specific affected matrix is included in the provided bundle.

Mitigation direction

  • Check your Linux vendor advisory for patched kernel packages or backports.
  • Update affected kernels to builds containing the referenced stable commits.
  • Prioritize systems using idxd, Intel DSA, or related DMA acceleration features.
  • If idxd is unnecessary, consider disabling it through approved operational change control.
  • Monitor kernel logs for recurring idxd workqueue call traces until patched.

Validation and detection

  • Inventory Linux kernel versions across exposed fleets and appliances.
  • Confirm whether the idxd driver or related hardware acceleration is present.
  • Verify vendor kernel changelogs include the referenced stable fixes.
  • Review kernel logs for call traces mentioning idxd, queue_work, or drain_workqueue.
  • Track remediation separately for distro kernels because backports may change version evidence.
Prepared
Confidence
medium
Sources
5

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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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
2ADP providers
4Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc40bd7d9737bdcfb02d42765bc6c59b338151123, c40bd7d9737bdcfb02d42765bc6c59b338151123, c40bd7d9737bdcfb02d42765bc6c59b338151123unaffected
LinuxLinux6.4, 0, 6.6.30, 6.8.9, 6.9affected
Weakness

CWE details

No CWE listed

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