From mboxrd@z Thu Jan 1 00:00:00 1970 From: AL-KERNEL To: kernel-cve@kernelcve.org Subject: [CVE-2026-68364][MODERATE REGULAR] drm/amd/display: Fix ISM dc_lock deadlock during suspend [ Upstream Date: Mon, 10 Aug 2026 09:19:22 -0400 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-AL-KERNEL-CVE: CVE-2026-68364 X-AL-KERNEL-Priority: MODERATE REGULAR X-AL-KERNEL-Severity: MODERATE REGULAR X-AL-KERNEL-Base-Severity: MODERATE X-AL-KERNEL-KPANIC: NO X-AL-KERNEL-ActionableScore: 3 X-AL-KERNEL-ActionableScore-Lower: 2 X-AL-KERNEL-Commit: 95776812e6b8f908563e8994d5d947b68baf68a6 List-Id: CVE: CVE-2026-68364 Priority: MODERATE REGULAR AL-KERNEL base severity: MODERATE KPANIC flag: NO Patch: drm/amd/display: Fix ISM dc_lock deadlock during suspend [ Upstream Commit: 95776812e6b8f908563e8994d5d947b68baf68a6 Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=95776812e6b8f908563e8994d5d947b68baf68a6 Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68364 Analysis date: Mon, 10 Aug 2026 09:19:22 -0400 ActionableScore: 3 ActionableScore lower bound: 2 Actionable bucket: Ordinary Moderate / Low-like operational DoS Manual review required: NO Summary: An AMDGPU display ISM lock-ordering bug can deadlock suspend/resume when ISM delayed work is in flight, allowing a local user in some desktop configurations to trigger a system hang but not memory corruption or privilege escalation. ====================================================================== ABOUT THIS REPORT ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68364 is available here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68364 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: NO A detailed explanation of the methodology and priority rules is included at the end of this message. ====================================================================== AL-KERNEL CLASSIFICATION RESULT ====================================================================== CVE-2026-68364 MODERATE CHECK WITH IMPACT FROM ORIG NN MODERATE 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-833;CWE-667;**CWE-400;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'An ABBA deadlock can occur in the AMD display ISM suspend path because amdgpu_dm_ism_disable() waited for ISM delayed work while dc_lock was held, while the delayed work handlers also need dc_lock. A local user may be able to trigger the hang by keeping display activity active, for example video playback, and initiating suspend or resume on a system using the affected AMD display driver. For the CVSS the PR:L is used for the paranoid score because a local desktop user or service session may be allowed to initiate suspend without full administrator privileges. The issue is not network reachable and does not provide an apparent memory corruption primitive. Impact is denial of service through a system hang during suspend or driver teardown.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like operational DoS (with actual score 3) SKIP CVE-2026-68364 UNKNOWN SKIP No affected files built, so skip this CVE NO - - unknown MAYBE LOCK DEADLOCK DANGER INIT HARDWARE DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH - - checked ====================================================================== ACTIONABLESCORE ANALYSIS ====================================================================== ActionableScore=3 ActionableScoreLower=2 ## 1. ActionableScore * Conservative score: 2 * Paranoid score: 3 * Final recommended bucket: **Ordinary Moderate / Low-like operational DoS**:: ## 2. Signal breakdown Conservative signals: * Local unprivileged trigger: +1 A local desktop user may be able to keep display activity active, for example video playback, and initiate suspend or resume through normal session policy. * Reliable kernel crash / strong DoS: +1 The commit reports a system hang during suspend/resume caused by an ABBA deadlock. * Hard or unreliable race / special timing required: -1 The deadlock requires an ISM delayed worker to be in flight while suspend or teardown waits for it under dc_lock. * Availability impact realistic: +1 The hang is system-wide and may require reboot or power-cycle recovery. Paranoid-only adjustment: * Do not subtract timing uncertainty in the paranoid score: +1 relative to conservative In affected AMD display setups with video playback and suspend/resume, the condition may be practically reproducible enough to treat as low complexity operational DoS. Not applied: * No remote/network trigger: +0 * No firmware-mediated external influence: +0 * No memory corruption primitive: +0 * No UAF, OOB write, double-free, refcount abuse, type confusion, or callback control: +0 * No privilege escalation plausibility: +0 * No confidentiality or integrity impact: +0 * No security boundary bypass: +0 ## 3. Reachability analysis The bug is reachable through the AMDGPU display suspend/resume or driver teardown path when ISM delayed work is active. A local logged-in user may be able to influence the condition by playing video and initiating suspend/resume, depending on desktop policy and logind permissions. Containers and namespaces generally do not help unless they can control host suspend or display power-management behavior. The path is not network reachable. Exposure is limited to systems using the affected AMD display driver and ISM functionality, but this is not an obscure debug-only path. Call-site confidence: high, because the patch shows the relevant suspend and fini call sites and the locking contract change. ## 4. Severity interpretation This behaves like an ordinary Moderate operational DoS rather than an Important-class vulnerability. The patch fixes a lock-ordering deadlock: amdgpu_dm_ism_disable() waited for delayed work while holding dc_lock, while the delayed work handlers also needed dc_lock. There is no evidence of memory lifetime corruption, attacker-controlled object reuse, arbitrary write, information disclosure, or privilege escalation. The realistic impact is a local system hang during suspend/resume. ## 5. One-sentence report phrase An AMDGPU display ISM lock-ordering bug can deadlock suspend/resume when ISM delayed work is in flight, allowing a local user in some desktop configurations to trigger a system hang but not memory corruption or privilege escalation. ## 6. Manual review recommendation NO MANUAL CHECK NEEDED This is a DoS-only deadlock with no indicated memory corruption, no network reachability, and no security-boundary bypass. Manual review is only warranted if suspend/resume reliability on AMD display systems is operationally critical for the target product. ====================================================================== UPSTREAM PATCH SUMMARY ====================================================================== Patch: drm/amd/display: Fix ISM dc_lock deadlock during suspend [ Upstream Commit: 95776812e6b8f908563e8994d5d947b68baf68a6 Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=95776812e6b8f908563e8994d5d947b68baf68a6 Changed files: drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_ism.c drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_ism.h 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=95776812e6b8f908563e8994d5d947b68baf68a6 ====================================================================== DETAILED REPORT METHODOLOGY ====================================================================== The original Linux kernel CVE announcement for CVE-2026-68364 can be found here: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68364 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).