[CVE-2026-74375][LOW] md/raid1,raid10: fix deadlock in read error recovery path [ Upstream

[CVE-2026-74375][LOW] md/raid1,raid10: fix deadlock in read error recovery path [ Upstream

[AL-KERNEL]

CVE: CVE-2026-74375
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: md/raid1,raid10: fix deadlock in read error recovery path [ Upstream
Commit: 38777f014c37972868f1733a651c85288bb8a757
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=38777f014c37972868f1733a651c85288bb8a757
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74375
Analysis date: Sun, 16 Aug 2026 07:42:59 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A deadlock in the md raid1 and raid10 read error recovery path can occur when a split MD cloned bio is resubmitted while the array is suspended, causing local storage IO or recovery to stall without evidence of memory corruption or privilege escalation.

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ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74375 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74375

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

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AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-74375	LOW	CHECK WITH IMPACT FROM ORIG NN MODERATE	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-667;*CWE-833;**CWE-400;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A deadlock can occur in the md raid1 and raid10 read error recovery path when a split MD cloned bio is resubmitted while the array is suspended. The cloned bio already holds an active_io reference, but the generic request path tried to acquire another live reference and could wait indefinitely during suspend. This can stall recovery or block IO to the array, causing a local denial of service. For the CVSS the PR:L is used for the paranoid case because a local user able to generate IO to an affected md raid device may participate in the trigger when read error recovery and array suspend happen concurrently. The attack complexity is high because it depends on a timing window plus a read error recovery condition and a suspended array. The issue is not network reachable and does not show a memory corruption primitive. Impact is availability only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)	YES	DEADLOCK DISK HARDWARE LINUS  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1. The issue can deadlock the md raid1/raid10 read error recovery path and block IO or recovery.
* Important filesystem/storage path: +1. The bug is in md RAID request handling and can affect block device availability.
* Hard or unreliable race / special timing required: -1. Triggering needs read error recovery plus cloned bio resubmission plus array suspend timing.
* Requires admin/root/CAP in typical deployments: -2. Reliable control of md array suspend or recovery conditions is normally administrative.

Conservative total is effectively 1 after keeping a minimum practical relevance for a storage deadlock.

Paranoid additional interpretation:

* Local unprivileged trigger participation: +1. A local user with access to the md-backed filesystem or block device may generate IO that participates in the failure path if read errors and suspend occur concurrently.
* No memory corruption signal. The patch fixes active_io reference acquisition semantics and waiting behavior. It does not show UAF, OOB access, double free, type confusion, arbitrary write, or stale callback use.

Paranoid total: 2.

## 3. Reachability analysis

The bug is local and storage-path dependent. It is not network reachable. In normal deployments, reliable triggering likely requires administrative control over md RAID state, array suspend, or fault-injection-like storage conditions. A lower-privileged local user may only contribute IO workload, while the key read error recovery and suspend timing are usually outside their direct control.

Namespaces and containers do not substantially lower privileges unless the container or service has delegated access to the affected md device or storage management operations. The affected subsystem is common enough in servers using md raid1 or raid10, but the exact trigger path is narrow.

Call-site confidence: high. The provided patch shows md_handle_request(), the active_io reference acquisition path, and the md_cloned_bio() distinction directly.

## 4. Severity interpretation

This behaves like an ordinary Moderate availability issue, not an Important-class vulnerability. The realistic impact is local denial of service through blocked IO or stalled RAID recovery. There is no supported privilege escalation primitive, no confidentiality impact, and no integrity impact beyond availability disruption.

Theoretical risk remains limited because the bug is a deadlock in reference acquisition during suspend, not memory lifetime corruption.

## 5. One-sentence report phrase

A deadlock in the md raid1 and raid10 read error recovery path can occur when a split MD cloned bio is resubmitted while the array is suspended, causing local storage IO or recovery to stall without evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as an auto-close or deferred Moderate candidate unless the target product has unusual exposure where unprivileged users can control md suspend, inject read errors, or directly manage affected RAID devices.

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UPSTREAM PATCH SUMMARY
======================================================================

Patch: md/raid1,raid10: fix deadlock in read error recovery path [ Upstream
Commit: 38777f014c37972868f1733a651c85288bb8a757
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=38777f014c37972868f1733a651c85288bb8a757

Changed files:
  drivers/md/md.c
  drivers/md/md.h

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=38777f014c37972868f1733a651c85288bb8a757

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-74375 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74375

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 1
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).