[CVE-2025-68793][MODERATE 7.0] drm/amdgpu: fix a job->pasid access race in gpu recovery [ Upstream

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

CVE: CVE-2025-68793
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: drm/amdgpu: fix a job->pasid access race in gpu recovery [ Upstream
Commit: dac58c012c47cadf337a35eb05d44498c43e5cd0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dac58c012c47cadf337a35eb05d44498c43e5cd0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-68793
Analysis date: Sat, 01 Aug 2026 14:06:41 -0400
ActionableScore: 5
ActionableScore lower bound: 4
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum**:: Actionable Moderate at minimum. Strong Important is not fully supported without evidence of controlled reclaim, write-after-free, type confusion, or callback control.
Manual review required: YES

Summary:
A race in AMDGPU GPU recovery can let the scheduler TDR workqueue free a job before `amdgpu_device_gpu_recover()` finishes using `job->pasid`, causing a kernel use-after-free read and likely local denial of service.

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

The original Linux kernel CVE announcement for CVE-2025-68793 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-68793

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: MODERATE 7.0
Manual review required: YES

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

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

CVE-2025-68793	MODERATE	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:H/I:H/A:H';*CWE-416;CWE-362;CWE-367;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'A use after free read in the amdgpu GPU recovery path can occur because amdgpu_device_gpu_recover may access job pasid after the scheduler timeout and TDR workqueue race frees the job. A local user who can submit GPU work and trigger GPU timeout or recovery may be able to hit the race, causing a KASAN detected slab use after free and likely a kernel crash or GPU reset failure. For the CVSS the PR:L is used because reliable triggering requires a local process with access to the DRM or render device rather than remote network access. The issue is not network reachable. Impact is at least denial of service via kernel crash. Because the bug is a real UAF read in kernel code, limited or high confidentiality and integrity impact is not proven but remains plausible enough for manual review in the paranoid score.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 5) 	MAYBE	READ DANGER RACE UAF HARDWARE DEBUGFS KPANIC 	-	-	checked

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

ActionableScore=5
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 5
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**:: Actionable Moderate at minimum. Strong Important is not fully supported without evidence of controlled reclaim, write-after-free, type confusion, or callback control.

## 2. Signal breakdown

Conservative signals:

* Local unprivileged trigger: +1. A local user with access to the DRM/render device can plausibly submit GPU work and trigger timeout/recovery paths.
* Memory corruption, weak/indirect primitive: +1. The patch and KASAN trace show a real UAF read of `job->pasid`, but only a stale read is demonstrated.
* Real lifetime corruption: +1. The job can be freed by the TDR workqueue while GPU recovery still uses it.
* Reliable kernel crash / strong DoS: +1. KASAN reports slab-use-after-free in kernel worker context, and the realistic outcome is kernel crash or GPU recovery failure.
* Hard or unreliable race / special timing required: -1. Triggering requires a race between scheduler timeout handling and TDR workqueue freeing the job.
* Broad/default/common subsystem: +1. AMDGPU and DRM render nodes are common on systems with AMD GPUs.

Conservative total: 4.

Paranoid additional interpretation:

* Privileged kernel/device-management lifetime path: +1. The UAF is in GPU recovery and scheduler/device reset handling, a trusted kernel device-management path.
* Paranoid score is capped at 5 under the race-UAF downgrade rule because there is no demonstrated reclaim, stale object replacement, write-after-free, type confusion, callback dispatch, or refcount takeover.

Paranoid total: 5.

Call-site confidence: high. The provided patch shows both the vulnerable late access to `job->pasid` and the fix that caches `pasid` before reset can free the job.

## 3. Reachability analysis

The bug is locally reachable on systems using the AMDGPU driver where a user can access the DRM/render device and submit GPU workloads. Typical desktop, workstation, gaming, or GPU compute setups may expose render nodes to non-root users through device permissions or group membership.

The issue is not network reachable. Containers may matter if `/dev/dri/renderD*` or the AMDGPU device is passed through to an untrusted container, because that can give a reduced-privilege workload access to the relevant GPU submission path. The trigger also requires GPU timeout or recovery behavior, so exploitation is less trivial than a direct ioctl crash.

## 4. Severity interpretation

This behaves more like an actionable Moderate than an ordinary low-risk driver bug. The demonstrated primitive is a kernel UAF read in a recovery race, with realistic DoS impact. However, the patch does not show attacker-controlled reclaim, write-after-free, object replacement, type confusion, or callback control, so practical privilege escalation is not strongly evidenced.

Theoretical memory-corruption concern exists because this is a real lifetime bug in kernel code. Realistic exploitation evidence currently supports crash/GPU reset failure more strongly than LPE.

## 5. One-sentence report phrase

A race in AMDGPU GPU recovery can let the scheduler TDR workqueue free a job before `amdgpu_device_gpu_recover()` finishes using `job->pasid`, causing a kernel use-after-free read and likely local denial of service.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED.

Reason: this is a confirmed kernel UAF in a locally reachable GPU driver path. Even though only a stale read and DoS are demonstrated, the lifetime bug should not be auto-closed without checking whether local GPU workloads can influence object reuse or recovery timing.

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

Patch: drm/amdgpu: fix a job->pasid access race in gpu recovery [ Upstream
Commit: dac58c012c47cadf337a35eb05d44498c43e5cd0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dac58c012c47cadf337a35eb05d44498c43e5cd0

Changed files:
  drivers/gpu/drm/amd/amdgpu/amdgpu_device.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=dac58c012c47cadf337a35eb05d44498c43e5cd0

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

The original Linux kernel CVE announcement for CVE-2025-68793 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2025-68793

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:L/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:H/I:H/A:H
  The Best / paranoid CVSS score: 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: 4
  Paranoid ActionableScore: 5

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: MODERATE
KPANIC detected for this report: YES
Published priority for this report (same as in Subject): MODERATE 7.0

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).