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CVE Record

CVE-2021-47382: s390/qeth: fix deadlock during failing recovery

In the Linux kernel, the following vulnerability has been resolved: s390/qeth: fix deadlock during failing recovery Commit 0b9902c1fcc5 ("s390/qeth: fix deadlock during recovery") removed taking discipline_mutex inside qeth_do_reset(), fixing potential deadlocks. An error path was missed though, that still takes discipline_mutex and thus has the original deadlock potential. Intermittent deadlocks were seen when a qeth channel path is configured offline, causing a race between qeth_do_reset and ccwgroup_remove. Call qeth_set_offline() directly in the qeth_do_reset() error case and then a new variant of ccwgroup_set_offline(), without taking discipline_mutex.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE is a Linux kernel reliability issue in the s390 qeth network driver. Under a failing recovery path, taking the wrong mutex can deadlock the system when a qeth channel path is configured offline. The business impact is likely availability disruption on affected Linux on IBM Z environments, not data theft based on the provided sources.

Executive priority

Treat this as targeted availability risk for Linux on s390 environments. It is not broadly internet-exposed from the provided evidence, but affected mainframe networking outages can be operationally significant. Prioritize validation where qeth supports critical production connectivity.

Technical view

The flaw is a missed error path after a prior qeth recovery deadlock fix. qeth_do_reset() could still take discipline_mutex during failing recovery, racing with ccwgroup_remove when a qeth channel path goes offline. The fix calls qeth_set_offline() directly and uses a ccwgroup_set_offline() variant that avoids taking discipline_mutex.

Likely exposure

Exposure appears limited to Linux systems using the s390 qeth driver. The source lists Linux kernel versions and commits, but downstream distribution kernel mapping is not provided. Organizations running Linux on IBM Z or s390 networking should verify whether their vendor kernel includes the referenced stable fixes.

Exploitation context

The provided sources do not report active exploitation, public exploit availability, or KEV listing. The described trigger is an intermittent recovery race when a qeth channel path is configured offline, suggesting an availability failure condition rather than a remote compromise path based on available evidence.

Researcher notes

Evidence is strongest for root cause and fix direction from kernel stable references. Severity, CVSS, CWE, exploitability, and downstream vendor package ranges are not provided in the source bundle. Avoid assuming exploitability beyond the documented deadlock race.

Mitigation direction

  • Check vendor kernel advisories for CVE-2021-47382 applicability.
  • Update affected Linux kernels to a build containing the referenced stable fixes.
  • Prioritize Linux on s390 systems using qeth networking.
  • Reduce nonessential qeth channel path offline changes until patched.
  • Document any temporary operational constraints for mainframe network maintenance.

Validation and detection

  • Inventory Linux on s390 hosts and identify qeth driver usage.
  • Map running kernel builds to vendor fixes for CVE-2021-47382.
  • Confirm the kernel includes the referenced stable commits or vendor backports.
  • Review system history for hangs during qeth recovery or offline operations.
  • Track remediation evidence in vulnerability management records.
Prepared
Confidence
medium
Sources
4

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
3Source 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
LinuxLinuxb41b554c1ee75070a14c02a88496b1f231c7eacc, b41b554c1ee75070a14c02a88496b1f231c7eacc, af0c184ea106051e428b5a0b5f2dfd31cbc54c52unaffected
LinuxLinux5.11, 0, 5.14.10, 5.15affected
Weakness

CWE details

No CWE listed

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