[CVE-2026-68105][LOW] drm/amdgpu: Fix kernel panic during driver load failure

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

CVE: CVE-2026-68105
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: drm/amdgpu: Fix kernel panic during driver load failure
Commit: 5bc93f907bad7e076d814664dfab8fc230efca3d
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5bc93f907bad7e076d814664dfab8fc230efca3d
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68105
Analysis date: Mon, 10 Aug 2026 18:34:57 -0400
ActionableScore: 3
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like. Paranoid borderline only if GPU lifecycle control is delegated
Manual review required: NO

Summary:
A NULL pointer dereference in the amdgpu driver load failure path can occur when MES KIQ initialization fails but the KIQ ring remains marked ready, causing a local kernel crash during cleanup.

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

The original Linux kernel CVE announcement for CVE-2026-68105 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68105

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-2026-68105	LOW	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:N/I:N/A:H';**CWE-476;CWE-703;CWE-665;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.7';DESCR 'A NULL pointer dereference in the amdgpu driver load failure path can occur when MES KIQ initialization fails but the KIQ ring remains marked as ready. Later cleanup may try to use that uninitialized ring during GPU TLB invalidation and reach gfx_v12_1_wait_reg_mem, causing a kernel crash. For the CVSS the PR:L is used for the paranoid view because some deployments may delegate GPU reset or driver lifecycle operations to service accounts or container root, while the typical base case remains PR:H for module load or driver bind operations. The issue is local and not network reachable. Impact is denial of service via kernel panic, with no concrete evidence of information disclosure, integrity impact, UAF, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like. Paranoid borderline only if GPU lifecycle control is delegated (with actual score 2)  SKIP CVE-2026-68105 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	DANGER NULLPTR INIT HARDWARE  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=3
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 3
* Final recommended bucket: **Ordinary Moderate / Low-like. Paranoid borderline only if GPU lifecycle control is delegated**

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1
  MES init failure may depend on firmware or device state, but this is not a normal remote/network input path.
* Reliable kernel crash / strong DoS: +1
  The commit includes a concrete NULL pointer dereference and kernel panic during driver load cleanup.
* Requires admin/root/CAP_* in typical deployments: -2
  The realistic trigger is driver load, bind, probe, or recovery path control, normally requiring root or equivalent host privileges.

Conservative total: 1 + 1 - 2 = 0

Paranoid additional interpretation:

* Local unprivileged or reduced-privileged trigger: +1
  Only for environments where GPU reset, driver bind, or device lifecycle operations are delegated to a service account, container root, or restricted operator.
* Availability impact realistic: +1
  Counted only in the paranoid view because the crash is host-wide if the faulty path is reached.
* Rare or configuration-specific condition: -1
  Requires affected AMD GPU generation using MES KIQ and a MES init failure during load.

Paranoid total: conservative 0 + 1 + 1 + 1 - 1 = 3

No UAF, OOB write, double-free, refcount misuse, arbitrary write, page-cache corruption, or ownership/COW bypass is shown.

## 3. Reachability analysis

The bug is local and not network reachable. The normal trigger path is amdgpu driver load or probe failure when MES KIQ initialization fails. In typical deployments this requires root or equivalent device-management privileges, because ordinary users cannot normally load the module, bind PCI drivers, or force this specific probe path.

Namespaces and containers only matter if the product deliberately delegates GPU reset or device lifecycle operations to reduced-privilege users. In that case the practical PR can look closer to PR:L, but the underlying primitive remains a NULL pointer dereference in a privileged driver cleanup path, not a controlled memory corruption issue.

The affected subsystem is common on systems with AMD GPUs, but the exact condition is hardware and failure-path specific.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like kernel DoS issue, not an Important-class vulnerability. The realistic impact is a kernel panic during a driver load failure path. The patch restores correct state by clearing the KIQ ring ready flag when MES KIQ initialization fails.

There is theoretical concern any kernel crash path deserves attention, but the evidence here supports only invalid NULL dereference. There is no demonstrated attacker-controlled reclaim, stale object reuse, write-after-free, type confusion, callback control, or privilege escalation path.

## 5. One-sentence report phrase

A NULL pointer dereference in the amdgpu driver load failure path can occur when MES KIQ initialization fails but the KIQ ring remains marked ready, causing a local kernel crash during cleanup.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a local privileged or at most delegated-device-management DoS with a concrete NULL dereference and no supported memory corruption or privilege escalation primitive.

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

Patch: drm/amdgpu: Fix kernel panic during driver load failure
Commit: 5bc93f907bad7e076d814664dfab8fc230efca3d
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=5bc93f907bad7e076d814664dfab8fc230efca3d

Commit description:

Avoid kernel panic if MES init fails during driver load. The KIQ ring is
falsely marked as ready as ASICs that use MES, KIQ is owned by MES.

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:gfx_v12_1_wait_reg_mem+0x5a/0x1f0 [amdgpu]
Call Trace:
 gfx_v12_1_ring_emit_reg_write_reg_wait+0x1f/0x30 [amdgpu]
 amdgpu_gmc_fw_reg_write_reg_wait+0xb2/0x190 [amdgpu]
 amdgpu_gmc_flush_gpu_tlb+0x1cc/0x230 [amdgpu]
 amdgpu_gart_invalidate_tlb+0x81/0xa0 [amdgpu]
 amdgpu_gart_unbind+0x72/0x90 [amdgpu]
 amdgpu_ttm_backend_unbind+0xa4/0xb0 [amdgpu]
 amdgpu_ttm_tt_unpopulate+0x13/0xd0 [amdgpu]
 amdttm_tt_unpopulate+0x29/0x70 [amdttm]
 ttm_bo_put+0x1eb/0x360 [amdttm]
 amdgpu_bo_free_kernel+0xf9/0x1f0 [amdgpu]
 amdgpu_ih_ring_fini+0x5a/0x90 [amdgpu]
 amdgpu_irq_fini_hw+0x58/0x80 [amdgpu]
 amdgpu_device_fini_hw+0x4e0/0x5b0 [amdgpu]
 amdgpu_driver_load_kms+0x60/0xa0 [amdgpu]
 amdgpu_pci_probe+0x28e/0x6d0 [amdgpu]
 pci_device_probe+0x19f/0x220
 really_probe+0x1ed/0x340
 driver_probe_device+0x1e/0x80
 __driver_attach+0xd3/0x1a0
 bus_for_each_dev+0x68/0xa0
 bus_add_driver+0x19f/0x270
 driver_register+0x5d/0xf0
 do_one_initcall+0xac/0x200
 do_init_module+0x1ec/0x280
 __se_sys_finit_module+0x2de/0x310
 do_syscall_64+0x6a/0x250
 entry_SYSCALL_64_after_hwframe+0x4b/0x53

Signed-off-by: Harish Kasiviswanathan <Harish.Kasiviswanathan@amd.com>
Reviewed-by: Kent Russell <kent.russell@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 4623b95 )
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/gpu/drm/amd/amdgpu/gfx_v12_0.c
  drivers/gpu/drm/amd/amdgpu/gfx_v12_1.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=5bc93f907bad7e076d814664dfab8fc230efca3d

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

The original Linux kernel CVE announcement for CVE-2026-68105 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68105

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:H
  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: 0
  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: 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).