CVE-2022-49827: drm: Fix potential null-ptr-deref in drm_vblank_destroy_worker()

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-01 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: drm: Fix potential null-ptr-deref in drm_vblank_destroy_worker() drm_vblank_init() call drmm_add_action_or_reset() with drm_vblank_init_release() as action. If __drmm_add_action() failed, will directly call drm_vblank_init_release() with the vblank whose worker is NULL. As the resule, a null-ptr-deref will happen in kthread_destroy_worker(). Add the NULL check before calling drm_vblank_destroy_worker(). BUG: null-ptr-deref KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f] CPU: 5 PID: 961 Comm: modprobe Not tainted 6.0.0-11331-gd465bff130bf-dirty RIP: 0010:kthread_destroy_worker+0x25/0xb0 Call Trace: <TASK> drm_vblank_init_release+0x124/0x220 [drm] ? drm_crtc_vblank_restore+0x8b0/0x8b0 [drm] __drmm_add_action_or_reset+0x41/0x50 [drm] drm_vblank_init+0x282/0x310 [drm] vkms_init+0x35f/0x1000 [vkms] ? 0xffffffffc4508000 ? lock_is_held_type+0xd7/0x130 ? __kmem_cache_alloc_node+0x1c2/0x2b0 ? lock_is_held_type+0xd7/0x130 ? 0xffffffffc4508000 do_one_initcall+0xd0/0x4f0 ... do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0

Affected products

Linux kernel: from 5.9 before 5.10.156; from 5.11 before 5.15.80; from 5.16 before 6.0.10; 6.1-rc1, 6.1-rc2, 6.1-rc3, 6.1-rc4, 6.1-rc5 — fixed in 5.10.156, 5.15.80, 6.0.10

How to fix

Upgrade to a fixed version: Linux kernel 5.10.156, 5.15.80, 6.0.10. Check the vendor advisory for mitigations.

References

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