Bug 2535336 (CVE-2026-89828) - CVE-2026-89828 kernel: drm/amdgpu: Fix init ordering in amdgpu_vram_mgr_init()
Summary: CVE-2026-89828 kernel: drm/amdgpu: Fix init ordering in amdgpu_vram_mgr_init()
Keywords:
Status: NEW
Alias: CVE-2026-89828
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-16 12:08 UTC by OSIDB Bzimport
Modified: 2026-10-20 13:06 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


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Description OSIDB Bzimport 2026-09-16 12:08:55 UTC
In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: Fix init ordering in amdgpu_vram_mgr_init()

drmm_cgroup_register_region() is called before INIT_LIST_HEAD() and
gpu_buddy_init() in amdgpu_vram_mgr_init(). If it fails, the function
returns early and bypasses those initializations.

Since adev->mman.initialized is set to true before amdgpu_vram_mgr_init()
is called, a failure triggers amdgpu_ttm_fini(), which calls
amdgpu_vram_mgr_fini(), which then:

 - Calls list_for_each_entry_safe() on reservations_pending and
   reserved_pages, whose list_head::next pointers are zero-initialized
   (NULL). The loop does not recognize them as empty and dereferences NULL.

 - Calls gpu_buddy_fini(), which iterates free_trees[] unconditionally
   via for_each_free_tree(). Since mm->free_trees is NULL
   (never allocated), this dereferences NULL.

Both result in a kernel panic on the module load error path.

Fix by moving drmm_cgroup_register_region() to after the list and buddy
allocator are fully initialized, so the teardown path is safe to run.


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