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CVE Record

CVE-2022-48658: mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context.

In the Linux kernel, the following vulnerability has been resolved: mm: slub: fix flush_cpu_slab()/__free_slab() invocations in task context. Commit 5a836bf6b09f ("mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context") moved all flush_cpu_slab() invocations to the global workqueue to avoid a problem related with deactivate_slab()/__free_slab() being called from an IRQ context on PREEMPT_RT kernels. When the flush_all_cpu_locked() function is called from a task context it may happen that a workqueue with WQ_MEM_RECLAIM bit set ends up flushing the global workqueue, this will cause a dependency issue. workqueue: WQ_MEM_RECLAIM nvme-delete-wq:nvme_delete_ctrl_work [nvme_core] is flushing !WQ_MEM_RECLAIM events:flush_cpu_slab WARNING: CPU: 37 PID: 410 at kernel/workqueue.c:2637 check_flush_dependency+0x10a/0x120 Workqueue: nvme-delete-wq nvme_delete_ctrl_work [nvme_core] RIP: 0010:check_flush_dependency+0x10a/0x120[ 453.262125] Call Trace: __flush_work.isra.0+0xbf/0x220 ? __queue_work+0x1dc/0x420 flush_all_cpus_locked+0xfb/0x120 __kmem_cache_shutdown+0x2b/0x320 kmem_cache_destroy+0x49/0x100 bioset_exit+0x143/0x190 blk_release_queue+0xb9/0x100 kobject_cleanup+0x37/0x130 nvme_fc_ctrl_free+0xc6/0x150 [nvme_fc] nvme_free_ctrl+0x1ac/0x2b0 [nvme_core] Fix this bug by creating a workqueue for the flush operation with the WQ_MEM_RECLAIM bit set.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can trigger a workqueue dependency problem during memory slab flushing, particularly around reclaim-capable workqueues such as NVMe controller cleanup. The provided sources describe a kernel warning and dependency issue, not confirmed compromise or data theft.

Executive priority

Treat as a kernel maintenance item with moderate operational urgency. Prioritize patch validation on infrastructure where kernel stalls or storage cleanup issues would affect availability, but do not escalate as known exploited based on the supplied evidence.

Technical view

The bug follows commit 5a836bf6b09f, which moved SLUB flush_cpu_slab and __free_slab handling to the global workqueue. When flush_all_cpu_locked runs from task context, a WQ_MEM_RECLAIM workqueue can flush non-reclaim global work, causing a dependency warning. The fix creates a reclaim-capable workqueue for the flush operation.

Likely exposure

Exposure is limited to Linux kernels carrying the affected SLUB change, with affected stable versions listed as 5.15 through 6.0-related ranges in the CVE data. Distribution backports may change exact exposure.

Exploitation context

The provided sources do not show active exploitation, and CISA KEV status is false. The evidence describes a reliability and dependency issue observed in kernel workqueue paths, not a public exploit or weaponized attack chain.

Researcher notes

The CVE evidence is narrow: it documents a SLUB workqueue dependency flaw and stable kernel fixes. No CVSS, CWE, exploitability analysis, or user-trigger path is provided. Avoid assuming remote exploitability or privilege escalation without additional vendor analysis.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fix status.
  • Prioritize systems using affected 5.15 to 6.0 kernel lines.
  • Review kernel release notes before relying on version strings alone.

Validation and detection

  • Inventory running kernel versions across Linux fleets.
  • Confirm whether vendor kernels include the stable fix commits.
  • Review kernel logs for WQ_MEM_RECLAIM flush dependency warnings.
  • Check systems with NVMe or block-layer cleanup activity first.
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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux5a836bf6b09f99ead1b69457ff39ab3011ece57b, 5a836bf6b09f99ead1b69457ff39ab3011ece57b, 5a836bf6b09f99ead1b69457ff39ab3011ece57bunaffected
LinuxLinux5.15, 0, 5.15.71, 5.19.12, 6.0affected
Weakness

CWE details

No CWE listed

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