[CVE-2026-98529][LOW] gpio: arizona: Fix runtime PM leak in arizona_gpio_direction_out()

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

CVE: CVE-2026-98529
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: gpio: arizona: Fix runtime PM leak in arizona_gpio_direction_out()
Commit: 40c010c1866382cb63ba7497d6ec74fcc60ab9cf
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=40c010c1866382cb63ba7497d6ec74fcc60ab9cf
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98529
Analysis date: Mon, 19 Oct 2026 03:05:29 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A failed persistent GPIO direction change can leak a runtime PM reference and keep the Arizona parent device active, but no memory corruption, kernel crash, authorization bypass, or reliable host-wide resource exhaustion is established.

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

The original Linux kernel CVE announcement for CVE-2026-98529 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98529

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-2026-98529	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98529 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;**CWE-400;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 can occur in arizona_gpio_direction_out when a persistent GPIO is changed from input to output and the following regmap_update_bits operation fails. The failed register update leaves the GPIO direction unchanged, but the runtime PM reference acquired for the attempted transition remains held and cannot be balanced by a later direction_in operation. Repeated successful access to this specific failure path could keep the parent device active and increase power consumption, but the available code does not establish reliable host wide resource exhaustion or a kernel crash. For the CVSS the PR:L value is used for the paranoid score because some systems may delegate GPIO device access to a non administrative local group, while the typical configuration requires administrative or driver level control. The issue is not network reachable. Impact is limited to availability and power management degradation, with no supported memory corruption, information disclosure, 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 HARDWARE LINUS 	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=NO
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

Positive signals:

* +1 Concrete persistent kernel resource or reference leak. The runtime PM reference acquired for a persistent GPIO transition is not released when `regmap_update_bits()` fails. Since the direction remains unchanged, a later `direction_in()` cannot balance this reference.

Negative signals:

* No negative points. GPIO hardware specificity was not treated as rare hardware without evidence that the affected devices are genuinely uncommon or require physical attacker access.
* No privilege penalty was applied because the complete userspace or kernel trigger and its permission model are not supplied.

Important non-awarded signals:

* No UAF, OOB access, double release, memory corruption, or attacker-controlled write is established.
* Reliable kernel crash and host-wide resource exhaustion are not established.
* Repeatable accumulation is unresolved because reliable attacker control over the `regmap_update_bits()` failure is not shown.
* No confidentiality, integrity, authorization-bypass, privilege-escalation, remote-reachability, or security-boundary signal applies.
* NEW52 B5-R does not apply because there is no heap OOB write, retry-accumulated index, or later consumption of corrupted structured state.
* NEW53 B3-PENDING does not apply because there is no shared-backing write.
* NEW54 B4-PENDING does not apply because no authorization decision or mandatory security guard is changed.

3. Reachability analysis

The vulnerable branch requires an Arizona GPIO marked persistent, a transition from input to output, acquisition of a runtime PM reference, and failure of the subsequent register update. The supplied evidence does not establish whether an ordinary user, a process with delegated GPIO device access, or only a kernel driver or administrator can perform the complete operation.

GPIO character-device access can be delegated by filesystem permissions, but delegation and exposure of this specific persistent line are not demonstrated. GPIO control is not inherently user-namespace or network-namespace scoped, so `NamespaceScopedPrivilege=NO`. No remote trigger is present.

An attacker would also need to reproduce the register-access failure. The patch does not show that this failure can be directly or reliably induced through the GPIO interface. There is no race. Arizona-compatible hardware is required, but no rare-hardware penalty is applied solely because this is driver code.

4. Primitive and severity interpretation

The exact primitive is a leaked runtime PM usage reference. It can keep the parent device active and prevent runtime suspend, producing persistent power-management degradation or retention of device resources.

This is not a stale post-lifetime reference, UAF, repeated release, or memory-corruption primitive. The parent device is retained rather than freed prematurely. The demonstrated effect is device power-state retention, not a kernel crash or system-wide denial of service.

`PrimitiveClass=CLASS_C` reflects invalid resource-accounting state with limited availability implications. `ImportantCandidate=NO` because no meaningful corruption or security-boundary primitive remains unresolved. `AutoDowngradeAllowed=YES` because the patch supports only a constrained resource leak and does not establish reliable hostile accumulation or host-wide exhaustion.

Operational severity is Low-like. A stronger rating would require evidence that a below-host-admin actor can repeatedly force the exact failing branch and thereby cause material host-wide resource exhaustion.

5. One-sentence report phrase

A failed persistent GPIO direction change can leak a runtime PM reference and keep the Arizona parent device active, but no memory corruption, kernel crash, authorization bypass, or reliable host-wide resource exhaustion is established.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

The issue is a concrete but constrained runtime PM reference leak with no demonstrated corruption, security-boundary impact, or reliably attacker-controlled exhaustion path.

7. Call-site confidence

Call-site confidence: medium

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

Patch: gpio: arizona: Fix runtime PM leak in arizona_gpio_direction_out()
Commit: 40c010c1866382cb63ba7497d6ec74fcc60ab9cf
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=40c010c1866382cb63ba7497d6ec74fcc60ab9cf

Commit description:

Switching a persistent GPIO line from input to output acquires a
runtime PM reference on the parent device, but if the subsequent
regmap_update_bits() fails the reference is never dropped and no later
direction_in() can balance it since the direction was never changed.
Drop the reference on the update failure path.

Fixes: 27a49ed ("gpio: arizona: Add support for GPIOs that need to be maintained")
Cc: stable@vger.kernel.org
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://patch.msgid.link/20260916094701.2007509-1-vulab@iscas.ac.cn
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpio/gpio-arizona.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=40c010c1866382cb63ba7497d6ec74fcc60ab9cf

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

The original Linux kernel CVE announcement for CVE-2026-98529 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98529

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).