CVE-2026-64100
Received Received - Intake

Deadlock in Linux Kernel MSM DRM Driver

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: drm/msm: Fix shrinker deadlock With PROVE_LOCKING on an Snapdragon X1 and VM reclaim pressure, we see: ====================================================== WARNING: possible circular locking dependency detected 7.0.0-debug+ #43 Tainted: G W ------------------------------------------------------ kswapd0/82 is trying to acquire lock: ffff800080ec3870 (reservation_ww_class_acquire){+.+.}-{0:0}, at: msm_gem_shrinker_scan+0x17c/0x400 [msm] but task is already holding lock: ffffc31709b263b8 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x88/0x988 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: __lock_acquire+0x4d0/0xad0 lock_acquire.part.0+0xc4/0x248 lock_acquire+0x8c/0x248 fs_reclaim_acquire+0xd0/0xf0 dma_resv_lockdep+0x224/0x348 do_one_initcall+0x84/0x5d0 do_initcalls+0x194/0x1d8 kernel_init_freeable+0x128/0x180 kernel_init+0x2c/0x160 ret_from_fork+0x10/0x20 -> #1 (reservation_ww_class_mutex){+.+.}-{4:4}: __lock_acquire+0x4d0/0xad0 lock_acquire.part.0+0xc4/0x248 lock_acquire+0x8c/0x248 dma_resv_lockdep+0x1a8/0x348 do_one_initcall+0x84/0x5d0 do_initcalls+0x194/0x1d8 kernel_init_freeable+0x128/0x180 kernel_init+0x2c/0x160 ret_from_fork+0x10/0x20 -> #0 (reservation_ww_class_acquire){+.+.}-{0:0}: check_prev_add+0x114/0x790 validate_chain+0x594/0x6f0 __lock_acquire+0x4d0/0xad0 lock_acquire.part.0+0xc4/0x248 lock_acquire+0x8c/0x248 drm_gem_lru_scan+0x1ac/0x440 msm_gem_shrinker_scan+0x17c/0x400 [msm] do_shrink_slab+0x150/0x4a0 shrink_slab+0x144/0x460 shrink_one+0x9c/0x1b0 shrink_many+0x27c/0x5c0 shrink_node+0x344/0x550 balance_pgdat+0x2c0/0x988 kswapd+0x11c/0x318 kthread+0x10c/0x128 ret_from_fork+0x10/0x20 other info that might help us debug this: Chain exists of: reservation_ww_class_acquire --> reservation_ww_class_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(reservation_ww_class_mutex); lock(fs_reclaim); lock(reservation_ww_class_acquire); *** DEADLOCK *** 1 lock held by kswapd0/82: #0: ffffc31709b263b8 (fs_reclaim){+.+.}-{0:0}, at: balance_pgdat+0x88/0x988 stack backtrace: CPU: 4 UID: 0 PID: 82 Comm: kswapd0 Tainted: G W 7.0.0-debug+ #43 PREEMPT(full) Tainted: [W]=WARN Hardware name: LENOVO 21BX0016US/21BX0016US, BIOS N3HET94W (1.66 ) 09/15/2025 Call trace: show_stack+0x20/0x40 (C) dump_stack_lvl+0x9c/0xd0 dump_stack+0x18/0x30 print_circular_bug+0x114/0x120 check_noncircular+0x178/0x198 check_prev_add+0x114/0x790 validate_chain+0x594/0x6f0 __lock_acquire+0x4d0/0xad0 lock_acquire.part.0+0xc4/0x248 lock_acquire+0x8c/0x248 drm_gem_lru_scan+0x1ac/0x440 msm_gem_shrinker_scan+0x17c/0x400 [msm] do_shrink_slab+0x150/0x4a0 shrink_slab+0x144/0x460 shrink_one+0x9c/0x1b0 shrink_many+0x27c/0x5c0 shrink_node+0x344/0x550 balance_pgdat+0x2c0/0x988 kswapd+0x11c/0x318 kthread+0x10c/0x128 ret_from_fork+0x10/0x20 kswapd0 holding fs_reclaim calls the MSM shrinker, which calls dma_resv_lock. This in turn acquires fs_reclaim. Fix this deadlock by using dma_resv_trylock() instead, dropping the subsequently unused passed wait-wound lock 'ticket'. Patchwork: https://patchwork.freedesktop.org/patch/723564/ [rob: fixup compile errors, replace lockdep splat with somethin ---truncated---

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-64100
EUVD
EUVD-2026-45785

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel 7.0.0-debug

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Exploitability

CWE
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability is a deadlock issue in the Linux kernel's memory management and graphics driver (MSM) components. It occurs when the kernel's memory reclaim process (kswapd0) tries to acquire a lock while already holding another, creating a circular dependency that freezes the system.

Detection Guidance

This vulnerability is a kernel-level deadlock issue in the Linux kernel's MSM graphics driver. It cannot be detected via network scans or typical commands. Look for kernel warnings or crashes related to circular locking dependencies in system logs, particularly involving fs_reclaim and reservation_ww_class_acquire.

Impact Analysis

This vulnerability can cause system freezes or crashes when the kernel attempts to reclaim memory under pressure. Users may experience unresponsive systems, application failures, or require a hard reboot to recover.

Compliance Impact

This vulnerability is a kernel deadlock issue in the Linux MSM graphics driver that could cause system instability or crashes under memory pressure. It does not directly relate to data protection, access control, or audit logging requirements in standards like GDPR or HIPAA.

Mitigation Strategies

Apply the kernel patch provided in the CVE details. Update your Linux kernel to a version that includes the fix. If immediate patching is not possible, avoid using the MSM graphics driver or disable shrinker functionality as a temporary workaround.

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