[CVE-2026-68250][LOW] drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON()

[CVE-2026-68250][LOW] drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON()

[AL-KERNEL]

CVE: CVE-2026-68250
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON()
Commit: 01dfea84df919cfbec4064151d327480ae5c120d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01dfea84df919cfbec4064151d327480ae5c120d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250
Analysis date: Mon, 10 Aug 2026 11:32:19 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could allow a local GPU user to trigger a kernel panic if a misaligned internal fence address reaches the function, but the patch does not indicate memory corruption or privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-68250 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250

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-2026-68250	LOW	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:L/UI:N/S:U/C:N/I:N/A:H';CWE-617;CWE-755;CWE-703;BEST CVSS score: '4.7';DESCR 'A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could panic the kernel if a fence address with non zero low alignment bits reaches sdma_v5_2_ring_emit_fence(). This is best classified as a local denial of service caused by an overly fatal assertion rather than memory corruption. For the CVSS the PR:L is used because a local process with access to GPU or DRM execution paths is the most plausible attacker model, while no administrator privileges are clearly required for ordinary render node access. The attack complexity is high because the checked address appears to be an internal driver fence address and is not obviously under direct user control. The issue is not network reachable. Impact is denial of service only via kernel panic, with no supported confidentiality or integrity impact.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-68250 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	WARNONLY SIMPLEFIX HARDWARE 	-	-	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

* Local unprivileged trigger: +1
  A local process with access to AMD GPU DRM or render node paths may plausibly reach SDMA fence emission, although direct control over the checked address is not shown.

* Reliable kernel crash / strong DoS: +1
  The original code used BUG_ON(addr & 0x3), which can panic the kernel if a misaligned fence address reaches this path.

* Hard or unreliable trigger / special condition: -1
  The fence address appears to be an internal driver-generated address, not an obviously attacker-controlled userspace value. Reliable triggering is therefore uncertain.

* Broad/default/common subsystem: +1 only in paranoid interpretation
  AMD GPU DRM render nodes are common on affected hardware, but this is still hardware and generation specific, so this is not counted in the conservative score.

No memory corruption, UAF, OOB write, type confusion, arbitrary write, page-cache corruption, or privilege-escalation primitive is supported by the patch.

## 3. Reachability analysis

The most plausible trigger is local use of GPU or DRM execution paths on systems with affected AMDGPU SDMA 5.2 hardware. Ordinary render node access may be enough to exercise GPU command submission paths, so PR:L is a reasonable CVSS-style assumption. However, the exact BUG_ON condition depends on a misaligned internal fence address, and the patch does not show that userspace can directly choose or reliably corrupt this value.

This is not network reachable. Containers or namespaces may matter only if the GPU device node is delegated into the container. The affected path is not universal because it depends on AMDGPU hardware and this SDMA generation.

## 4. Severity interpretation

This behaves like an ordinary local DoS issue caused by an overly fatal kernel assertion. The realistic impact is kernel panic if the internal invariant fails. Theoretical impact does not extend to memory corruption or privilege escalation based on the provided patch.

The paranoid score remains low because the only concrete primitive is BUG_ON-triggered panic. There is no evidence of attacker-controlled overwrite, stale pointer reuse, object confusion, or sensitive data exposure.

## 5. One-sentence report phrase

A reachable BUG_ON() in the amdgpu SDMA 5.2 fence emission path could allow a local GPU user to trigger a kernel panic if a misaligned internal fence address reaches the function, but the patch does not indicate memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

This can be handled as a low-priority local DoS/assertion fix unless your product exposes AMDGPU render nodes to untrusted tenants and has evidence that userspace can reliably force the misaligned fence address.

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

Patch: drm/amdgpu/sdma5.2: replace BUG_ON() with WARN_ON()
Commit: 01dfea84df919cfbec4064151d327480ae5c120d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=01dfea84df919cfbec4064151d327480ae5c120d

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 ae658af )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/sdma_v5_2.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=01dfea84df919cfbec4064151d327480ae5c120d

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

The original Linux kernel CVE announcement for CVE-2026-68250 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68250

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: Not available
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 1
  Paranoid ActionableScore: 2

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).