[CVE-2026-89454][LOW] PCI: plda: Fix IRQ domain leaks in the error paths of plda_init_interrupts()

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

CVE: CVE-2026-89454
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: PCI: plda: Fix IRQ domain leaks in the error paths of plda_init_interrupts()
Commit: 01b05cebe1e862e31e382359848d7dca02525a4f
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01b05cebe1e862e31e382359848d7dca02525a4f
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89454
Analysis date: Sat, 12 Sep 2026 00:54:00 -0400
ActionableScore: 0
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-89454 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89454

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.

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

CVE-2026-89454	LOW	https://www.kernelcve.org/list/?q=CVE-2026-89454 CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';*CWE-772;CWE-404;*CWE-401;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.1';DESCR 'plda_init_interrupts can allocate IRQ domains and create IRQ mappings, then return on later errors without releasing those resources. Repeated failed probe or rebind cycles can leak IRQ domain and mapping state and may eventually cause resource exhaustion or driver initialization failures. For the CVSS the PR:H is used because reliable triggering normally requires administrative control over driver probing, device binding, or platform level fault conditions. The issue is not network reachable and has no evidence of memory corruption, information disclosure, or privilege escalation. Impact is availability only and is expected to be limited unless failures can be repeated many times.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)  SKIP CVE-2026-89454 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES  NO NO unknown 	MAYBE	INIT SIMPLEFIX LEAK ERRORPATH LINUS 	-	-	checked

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

ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: -1
* Conservative score: 0
* Applied conservative floor/cap: lower bound at 0, -1 -> 0
* Raw paranoid score: 0
* Paranoid score: 0
* Applied paranoid floor/cap: none
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

Positive signals:

* +1 Concrete persistent kernel resource/reference leak. The patch directly establishes that IRQ domains and IRQ mappings are created in plda_init_interrupts() and are not deinitialized on later error paths.
* +1 Paranoid resource exhaustion concern. Repeated failed probe or rebind cycles could accumulate leaked IRQ domain or mapping state and may cause later initialization failures or resource pressure.

Negative signals:

* -2 Host-admin-equivalent triggering requirement. Reliable triggering requires control over PCI/platform driver probing, device binding, or platform-level failure conditions, which is host-admin-equivalent in the supplied context.

Non-awarded signals:

* RealUAF not awarded. No stale object dereference, post-free use, double release, or refcount mutation is established.
* Memory corruption not awarded. The patch fixes missing cleanup of IRQ domains and mappings, not an overwrite, UAF, OOB access, type confusion, or list corruption.
* C/I impact not awarded. There is no evidence of information disclosure, unauthorized modification, privilege escalation, or security-boundary bypass.
* Remote reachability not awarded. The vulnerable path is driver initialization error handling, not packet or network input processing.
* Extra Availability not awarded conservatively. A single failed initialization leaks resources but does not establish immediate host-wide failure.

3. Reachability analysis

The trigger is local/platform-control-plane only. A practical attacker would need to cause plda_init_interrupts() to fail after IRQ domains or mappings have been allocated, for example through failed platform_get_irq(), failed irq_create_mapping(), or failed event IRQ request paths. The supplied patch does not show an ordinary user interface, namespace-scoped capability path, network path, or delegated non-admin path that can drive the complete failure sequence.

HostAdminRequired is YES because driver probe, bind or rebind, and platform-device failure manipulation are normally host-admin-equivalent operations here and no lower-privilege trigger is supplied. NamespaceScopedPrivilege is NO because there is no namespace-scoped operation involved. Prior platform or device setup is required. No special remote attack surface is established. No timing race is involved.

4. Primitive and severity interpretation

The exact primitive is a persistent IRQ domain and IRQ mapping leak on plda_init_interrupts() error paths. This is a resource-management defect, not a memory-corruption or lifetime-corruption primitive. There is no active structured stale object, no fixed stale storage use, and no concrete repeated release/refcount operation.

Demonstrated consequence is resource leakage and possible later driver initialization failure. Speculative consequence is broader resource exhaustion after repeated host-admin-driven failure cycles. There is no leverage beyond availability. ImportantCandidate is NO because the issue lacks UAF, controlled corruption, authorization bypass, COW/ownership violation, or meaningful unresolved exploitation primitive. AutoDowngradeAllowed is YES because this is a host-admin-gated resource leak without memory corruption or network reachability.

5. One-sentence report phrase

PCI PLDA interrupt initialization can leak IRQ domains and IRQ mappings on error paths, but reliable triggering appears to require host administrative control over driver probing or platform failure conditions, so the practical impact is limited availability/resource exhaustion.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a local host-admin-gated resource leak with no established memory corruption, UAF, security-boundary bypass, remote trigger, or privilege-escalation path.

7. Call-site confidence

Call-site confidence: high

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

Patch: PCI: plda: Fix IRQ domain leaks in the error paths of plda_init_interrupts()
Commit: 01b05cebe1e862e31e382359848d7dca02525a4f
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01b05cebe1e862e31e382359848d7dca02525a4f

Commit description:

plda_init_interrupts() initializes IRQ domains and creates IRQ mapping but
does not unwind them when later step fails.

If platform_get_irq() or either irq_create_mapping() fails
in plda_init_interrupts(), the domains are never deinitialized. If
irq_create_mapping() fails, port->intx_irq stays initialized.

Hence, remove the IRQ domains in the error path by calling
plda_pcie_irq_domain_deinit().

Since plda_pcie_irq_domain_deinit() now disposes of the intx_irq and
msi_irq mappings itself before removing their domains, the msi_irq
mapping failure path can go directly to err_irq_domain_deinit instead of
disposing of port->intx_irq separately first.

This issue was found by automated review of sashiko-bot

Fixes: 4602c37 ("PCI: microchip: Move IRQ functions to pcie-plda-host.c")
Fixes: 76c9113 ("PCI: plda: Add host init/deinit and map bus functions")
Closes: https://lore.kernel.org/linux-pci/20260718120701.DF4111F000E9@smtp.kernel.org/
Signed-off-by: Ali Tariq <alitariq45892@gmail.com>
[mani: commit log]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260723142824.726655-1-alitariq45892@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/pci/controller/plda/pcie-plda-host.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=01b05cebe1e862e31e382359848d7dca02525a4f

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

The original Linux kernel CVE announcement for CVE-2026-89454 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89454

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.1

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: 0

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).