Bug 2363409 (CVE-2022-49827)

Summary: CVE-2022-49827 kernel: drm: Fix potential null-ptr-deref in drm_vblank_destroy_worker()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-01 15:03:32 UTC
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

Comment 1 Avinash Hanwate 2025-05-02 06:20:08 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050135-CVE-2022-49827-f7bc@gregkh/T