[CVE-2026-98519][LOW] drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()

[CVE-2026-98519][LOW] drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()

[AL-KERNEL]

CVE: CVE-2026-98519
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()
Commit: fc5606ac91642d0f184b83ab833148c457c3c331
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fc5606ac91642d0f184b83ab833148c457c3c331
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98519
Analysis date: Sat, 24 Oct 2026 08:50:24 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
An interrupted AMDGPU debugfs test path leaks a runtime-PM reference, potentially keeping the GPU awake without causing memory corruption or a demonstrated host-wide denial of service.

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

The original Linux kernel CVE announcement for CVE-2026-98519 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98519

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-2026-98519	LOW	https://www.kernelcve.org/list/?q=CVE-2026-98519 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 missing cleanup path in amdgpu_debugfs_test_ib_show retains the runtime PM reference when down_write_killable is interrupted, keeping the GPU awake and increasing power use until the reference imbalance is cleared or the driver or system is restarted. Reliable triggering requires access to the AMDGPU debugfs test interface, contention on the reset semaphore, and a correctly timed signal, so the issue is local and has high attack complexity. For the CVSS the PR:L value in the paranoid vector reflects deployments where debugfs access is delegated to a local service or a reduced capability administrator. There is no supported UAF, OOB access, information leak, write primitive, or host wide resource exhaustion path, so C:N I:N A:L remains appropriate. 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 REQUIRED. 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 DEBUGFS 	-	-	checked

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

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

2. Signal breakdown

* +1 Concrete persistent kernel resource/reference leak: `pm_runtime_get_sync()` acquires a runtime-PM reference, but interruption of `down_write_killable()` previously returned without the corresponding `pm_runtime_put_autosuspend()`.
* +0 Device-local consequence: the demonstrated effect is keeping the GPU awake and increasing power use, not a kernel crash or host-wide resource exhaustion.
* No timing penalty: contention and signal timing complicate triggering, but the supplied evidence does not establish a materially uncontrollable race.
* No UAF, OOB access, memory overwrite, authorization bypass, confidentiality impact, integrity impact, or strong availability impact is shown.
* B5-R and B3-PENDING do not apply: there is neither an OOB write nor a shared-backing write.

3. Reachability analysis

The operation is exposed through an AMDGPU debugfs test interface. The supplied source does not establish its file permissions, mount policy, or whether a below-host-admin service receives access; therefore effective host-admin requirements and host UID 0 requirements remain unknown. This is not a namespace-scoped capability path. Triggering requires lock interruption after runtime-PM acquisition, plausibly involving reset-semaphore contention and a signal. AMD GPU hardware and debugfs exposure are prerequisites, but no physical attacker-controlled device is required.

4. Primitive and severity reading

The exact defect is a missing runtime-PM put on one interrupted error path. It leaks a device power-management reference but does not leave a dangling object, perform a second lifetime mutation through freed storage, or corrupt active structured state. The supported result is prolonged GPU wakefulness and excess power use. This is CLASS_C resource/availability behavior, with no Important-grade leverage or unresolved security boundary; automatic downgrade is therefore allowed.

5. One-sentence report phrase

An interrupted AMDGPU debugfs test path leaks a runtime-PM reference, potentially keeping the GPU awake without causing memory corruption or a demonstrated host-wide denial of service.

6. Manual review advice

NO MANUAL CHECK NEEDED

The patch establishes only a constrained runtime-PM reference leak with no corruption, authorization, or trust-boundary primitive.

7. Call-site confidence

Call-site confidence: high

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

Patch: drm/amdgpu: Fix runtime PM leak in amdgpu_debugfs_test_ib_show()
Commit: fc5606ac91642d0f184b83ab833148c457c3c331
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=fc5606ac91642d0f184b83ab833148c457c3c331

Commit description:

amdgpu_debugfs_test_ib_show() resumes the device with
pm_runtime_get_sync() before taking the reset domain semaphore with
down_write_killable().  If the write lock acquisition is interrupted,
the function returns without calling pm_runtime_put_autosuspend(),
leaking the runtime PM reference acquired for the device and keeping
the GPU awake.

Drop the runtime PM reference on the interrupted down_write_killable()
error path before returning.

Fixes: 6049db4 ("drm/amdgpu: change reset lock from mutex to rw_semaphore")
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit ec30a57 )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/amdgpu_debugfs.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=fc5606ac91642d0f184b83ab833148c457c3c331

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

The original Linux kernel CVE announcement for CVE-2026-98519 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98519

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).