[CVE-2026-98527][LOW] gpio: zynq: fix runtime PM leak on request error path

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-98527
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: gpio: zynq: fix runtime PM leak on request error path
Commit: e380fba02908b809f5bbef371259003cf5887bb4
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e380fba02908b809f5bbef371259003cf5887bb4
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98527
Analysis date: Mon, 19 Oct 2026 04:07:20 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A failed Zynq GPIO runtime resume leaks a runtime PM usage reference and prevents controller suspension, but the demonstrated impact is limited to persistent clock and power retention without memory corruption or host-wide denial of service.

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

The original Linux kernel CVE announcement for CVE-2026-98527 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98527

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-2026-98527	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98527 CHECK WITH IMPACT FROM ORIG NN LOW | AEGIS IMPACT LOW AEGIS_AS=1 LEGACY=LOW RESULT=SAME (final reconciliation agrees; DECISION: both LOW)	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:L';*CWE-772;CWE-404;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '2.5';DESCR 'A runtime PM reference leak occurs when zynq_gpio_request calls pm_runtime_get_sync and runtime resume fails. The failed call leaves the usage counter incremented, while gpiolib does not invoke zynq_gpio_free after a request error, so the matching pm_runtime_put is never reached. The controller can then remain unable to runtime suspend and its clock may stay enabled, causing persistent power and resource retention rather than memory corruption. For the CVSS the PR:L reflects the paranoid case where a local service or container has delegated access to the affected gpiochip. Reliable triggering still requires the specific runtime resume failure path, so AC:H is appropriate. The issue is not network reachable. The demonstrated impact is limited availability degradation and increased power use, with no supported UAF, out of bounds access, information disclosure, data modification, kernel crash, or privilege escalation primitive. Automated impact decision path. The original SimpleNet classifier selected LOW. The primary LLM estimated paranoid CVSS 2.5 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. No severity changing production threshold or specialist override was recorded. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review NO. Its independently reconciled impact was LOW. The shadow agreed with the final production impact and aggregation did not change that impact. The final reported impact is LOW.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	SIMPLEFIX LEAK ERRORPATH HARDWARE LINUS 	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Concrete persistent kernel resource/reference leak. `pm_runtime_get_sync()` increments the runtime PM usage counter on failure, but the failed GPIO request has no matching `pm_runtime_put()`.
* No crash or strong DoS point. The demonstrated result is a controller that cannot runtime-suspend and a clock that remains enabled.
* No additional resource-exhaustion point. Repeated failures can increase the counter, but no memory growth, host-wide exhaustion, or isolation bypass is established.
* No UAF, OOB access, arbitrary write, shared-backing write, authorization bypass, or active-state corruption is present.
* No confidentiality or integrity consequence is supported.
* B5-R does not apply because there is no heap OOB write or later consumption of corrupted structured state.
* B3-PENDING does not apply because no shared or file-backed storage is modified.
* B4-PENDING does not apply because no DENY-to-ALLOW authorization decision is changed.

3. Reachability analysis

A caller must request a GPIO line while runtime resume fails. The supplied evidence does not establish whether the complete trigger requires host administration or is available through delegated `/dev/gpiochip` permissions, so `HostAdminRequired` remains `UNKNOWN`.

The patch provides no evidence that all required operations are available through an attacker-created user or device namespace. `NamespaceScopedPrivilege` is therefore `UNKNOWN`. Zynq hardware and the affected GPIO controller are prerequisites, but no extra rarity penalty is applied merely because this is a device driver. This is an ordered error path, not a race.

4. Primitive and severity interpretation

The exact primitive is a persistent runtime PM usage-reference leak. It leaves the controller active and prevents runtime suspension, but it does not create a dangling reference, post-lifetime access, memory corruption, or authorization failure.

The behavior is classified as `CLASS_C` because it creates constrained invalid power-management state with device-local resource retention. The demonstrated consequence is increased power use and a clock remaining enabled. Host-wide denial of service and security-boundary impact are not established.

`ImportantCandidate=NO` because there is no Important-preserving corruption, lifetime, ownership, or authorization primitive. `AutoDowngradeAllowed=YES` because the issue is a bounded resource-retention defect without established accumulation into host-wide exhaustion.

5. One-sentence report phrase

A failed Zynq GPIO runtime resume leaks a runtime PM usage reference and prevents controller suspension, but the demonstrated impact is limited to persistent clock and power retention without memory corruption or host-wide denial of service.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The concrete defect is a low-impact runtime PM reference leak with no supported memory-corruption, authorization, cross-boundary, or strong availability primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: gpio: zynq: fix runtime PM leak on request error path
Commit: e380fba02908b809f5bbef371259003cf5887bb4
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e380fba02908b809f5bbef371259003cf5887bb4

Commit description:

pm_runtime_get_sync() leaves the usage counter incremented even when it
fails, and zynq_gpio_request() returns the error without dropping it.

gpiolib does not call ->free() when ->request() fails, so zynq_gpio_free(),
which holds the only matching pm_runtime_put(), never runs. The reference
is leaked and the controller can no longer runtime-suspend, so its clock
stays enabled.

Switch to pm_runtime_resume_and_get(), which only increments the usage
counter on success.

Fixes: 3242ba1 ("gpio: Add driver for Zynq GPIO controller")
Cc: stable@vger.kernel.org
Signed-off-by: Ridham Khurana <khurana.ridham222@gmail.com>
Link: https://patch.msgid.link/20260922092102.1053513-1-khurana.ridham222@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpio/gpio-zynq.c

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=e380fba02908b809f5bbef371259003cf5887bb4

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

The original Linux kernel CVE announcement for CVE-2026-98527 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98527

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:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS score: 2.5

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: unknown
  Paranoid ActionableScore: 1

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).