[CVE-2026-68111][MODERATE REGULAR] drm/amdgpu/gfx9: replace BUG_ON() with WARN_ON()

[CVE-2026-68111][MODERATE REGULAR] drm/amdgpu/gfx9: replace BUG_ON() with WARN_ON()

[AL-KERNEL]

CVE: CVE-2026-68111
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: drm/amdgpu/gfx9: replace BUG_ON() with WARN_ON()
Commit: 6c8b9c1f03c7169c9577098b0c3035617606f8d4
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c8b9c1f03c7169c9577098b0c3035617606f8d4
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68111
Analysis date: Mon, 10 Aug 2026 17:43:25 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline Moderate. Manual review recommended
Manual review required: YES

Summary:
AMDGPU gfx9 used BUG_ON() for several GPU address alignment checks in ring emission paths, allowing a local process that can reach the affected DRM GPU submission path to trigger a kernel panic and cause denial of service.

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

The original Linux kernel CVE announcement for CVE-2026-68111 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68111

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 REGULAR
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-2026-68111	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-617;CWE-754;CWE-703;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'amdgpu gfx9 used BUG_ON() for several GPU address alignment checks in ring emission paths. If an unaligned address reaches these paths, the kernel can panic, which makes the issue a local denial of service. For the CVSS the PR:L is used because reliable triggering would require a local process with access to the DRM GPU interface or a similar local GPU submission path. The issue is not network reachable. Impact is kernel availability loss only. No concrete UAF, OOB write, information leak, or privilege escalation primitive is visible from this patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate. Manual review recommended (with actual score 3)  SKIP CVE-2026-68111 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	WARNONLY SIMPLEFIX HARDWARE PACKET  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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

ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Borderline Moderate. Manual review recommended**::

## 2. Signal breakdown

Triggered signals:

* Local unprivileged trigger: +1
  A local process with access to the DRM AMDGPU interface or render node may be able to reach GPU submission paths. This depends on device permissions and whether the affected address values are user-influenceable.

* Reliable kernel crash / strong DoS: +1
  The old code used BUG_ON() for alignment checks. If reached with an unaligned address, this causes an immediate kernel panic.

* Broad/default/common subsystem or broadly deployed exposure: +1, paranoid only
  AMDGPU is a commonly deployed DRM driver on systems with AMD GPUs. This is hardware-dependent, so I count it only in the paranoid score.

Subtracted signals:

* Hard or uncertain triggerability: -1, conservative only
  The patch does not show that userspace can directly supply these unaligned addresses. Some of the values may normally be generated or validated internally by the driver.

Not awarded:

* Generic memory corruption: +0
  No UAF, double-free, OOB write, heap overwrite, refcount abuse, or type confusion is shown.

* Privilege escalation plausible: +0
  The patch only replaces BUG_ON() with WARN_ON(). There is no supported LPE primitive.

* Confidentiality impact plausible: +0
  No information leak is shown.

* Integrity impact plausible: +0
  No attacker-controlled write or policy bypass is shown.

* Availability impact realistic: +0 separately
  Availability is already counted through the strong DoS signal. I do not double-count it.

## 3. Reachability analysis

The likely trigger would be local, through AMDGPU DRM ring submission or related GPU command paths. In many desktop or GPU-compute deployments, render nodes may be accessible to non-root users or users in a graphics-related group, so PR:L is a reasonable paranoid interpretation.

The path is not network reachable. Containers and namespaces only matter if the GPU device node is passed through or exposed to the container. The affected code is hardware-specific to AMD gfx9, so systems without affected AMD GPUs are not exposed.

Call-site confidence: medium. The patch shows the affected ring emission functions, but it does not show the full userspace-to-ring call chain or whether userspace can directly force the unaligned values.

## 4. Severity interpretation

This behaves like an ordinary to borderline Moderate local DoS issue. The concrete primitive is a reachable assertion leading to kernel panic, not memory corruption. The theoretical risk is limited because continued execution after WARN_ON() may still represent invalid state, but the patch context does not support UAF, OOB write, arbitrary write, information disclosure, or privilege escalation.

The paranoid score is higher only because local GPU device access can be broadly available on systems with AMD GPUs and a BUG_ON() panic is a host-wide availability impact if reachable.

## 5. One-sentence report phrase

AMDGPU gfx9 used BUG_ON() for several GPU address alignment checks in ring emission paths, allowing a local process that can reach the affected DRM GPU submission path to trigger a kernel panic and cause denial of service.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review should verify whether unprivileged render-node users can actually influence `ib->gpu_addr`, fence addresses, or WAIT_REG_MEM addresses enough to trigger the BUG_ON() paths on affected gfx9 hardware. If those values are fully kernel-controlled and always aligned in practice, this can be downgraded toward ordinary Low/Moderate DoS handling.

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

Patch: drm/amdgpu/gfx9: replace BUG_ON() with WARN_ON()
Commit: 6c8b9c1f03c7169c9577098b0c3035617606f8d4
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6c8b9c1f03c7169c9577098b0c3035617606f8d4

Commit description:

There's no need to crash the kernel for these cases.

Reviewed-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit b71604f )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/gfx_v9_0.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=6c8b9c1f03c7169c9577098b0c3035617606f8d4

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

The original Linux kernel CVE announcement for CVE-2026-68111 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68111

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:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

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: 2
  Paranoid ActionableScore: 3

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: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).