CVE-2026-64100

What it is

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---

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-19 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-08-11 16:04 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.1% in the next 30 days (EPSS).
• Severity: 5.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-07-19 16:17 UTC

Last modified

2026-08-11 16:04 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-667

Record status

Analyzed

Affected

• Linux Kernel < 6.18.34
• Linux Kernel < 7.0.11
• Linux Kernel 7.1

Attack profile CVSS 3.1 · 5.5

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

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