[CVE-2026-68249][LOW] drm/amdgpu/sdma5.0: replace BUG_ON() with WARN_ON()

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

CVE: CVE-2026-68249
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amdgpu/sdma5.0: replace BUG_ON() with WARN_ON()
Commit: f6212bc1bbd936fd9f7d77168b0c8b0019477b64
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f6212bc1bbd936fd9f7d77168b0c8b0019477b64
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68249
Analysis date: Mon, 10 Aug 2026 13:37:28 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-68249 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68249

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-2026-68249	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-754;CWE-703;BEST CVSS score: '4.7';DESCR 'A reachable BUG_ON in the AMDGPU SDMA v5.0 fence emit path could convert an unexpected misaligned fence address into a kernel panic. A local user with access to the GPU driver interface may indirectly reach this path through GPU work submission, but the fence address appears to be driver managed rather than directly attacker controlled. For the CVSS the PR:L is used because a local user context with access to the DRM GPU interface is the most plausible trigger model for the paranoid score. The issue is not network reachable. Impact is denial of service only via kernel crash, with no concrete evidence of information disclosure, integrity impact, UAF, OOB access, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)  SKIP CVE-2026-68249 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

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

2. Signal breakdown
* Local unprivileged trigger: +1. A local user with access to AMDGPU DRM interfaces may plausibly reach SDMA fence emission indirectly through GPU work submission.
* Reliable kernel crash / strong DoS: +1. If the misaligned fence address condition is reached, BUG_ON() causes an immediate kernel panic.
* Hard or unreliable trigger: -1. The address appears to be driver-managed rather than directly attacker-controlled, and the patch does not show a straightforward user-controlled path to set the low address bits.
* Broad/default/common subsystem: +1. AMDGPU is a commonly deployed GPU driver, but the affected path is device-specific and not a core kernel-wide interface.
* No memory-corruption signal. The patch only replaces BUG_ON() with WARN_ON() and does not show UAF, OOB access, arbitrary write, refcount misuse, object lifetime corruption, or privilege-escalation primitive.

3. Reachability analysis
A local user with access to the GPU device nodes is the most plausible attacker model. No network reachability is present. Namespaces or containers may matter only if GPU device access is delegated into the container. The vulnerable condition depends on reaching SDMA fence emission with a misaligned internal fence address, which is not shown to be directly controllable by userspace. Call-site confidence: medium, because the changed function is visible but the full caller chain and address provenance are not included.

4. Severity interpretation
This behaves like an ordinary Moderate or Low-like local DoS issue. The demonstrated impact is kernel panic from a reachable assertion. There is no supported evidence of memory corruption, confidentiality impact, integrity impact, or privilege escalation. Theoretical concern is limited to whether userspace can reliably force the invalid alignment condition, but the patch context does not support upgrading it beyond DoS.

5. One-sentence report phrase
A reachable BUG_ON() in the AMDGPU SDMA v5.0 fence emission path could allow a local GPU user to trigger a kernel panic if an unexpected misaligned fence address is reached, but no memory corruption or privilege escalation primitive is shown.

6. Manual review recommendation
NO MANUAL CHECK NEEDED
Reason: this is a local DoS-only assertion removal with low ActionableScore, no network exposure, no concrete memory corruption primitive, and no evidence of confidentiality or integrity impact.

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

Patch: drm/amdgpu/sdma5.0: replace BUG_ON() with WARN_ON()
Commit: f6212bc1bbd936fd9f7d77168b0c8b0019477b64
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f6212bc1bbd936fd9f7d77168b0c8b0019477b64

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 8d144a0 )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/sdma_v5_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=f6212bc1bbd936fd9f7d77168b0c8b0019477b64

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

The original Linux kernel CVE announcement for CVE-2026-68249 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68249

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: unknown
  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).