Bug 2492265 (CVE-2026-52965)

Summary: CVE-2026-52965 kernel: drm/ttm: Fix ttm_bo_swapout() infinite LRU walk on swapout failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's TTM (Trusted Memory Manager) component. When the ttm_tt_swapout() function fails, a resource is incorrectly added to the Least Recently Used (LRU) list. This misplacement can lead to an infinite loop during subsequent list processing, causing the system to become unresponsive. This issue can result in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-06-24 18:01:56 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drm/ttm: Fix ttm_bo_swapout() infinite LRU walk on swapout failure

When ttm_tt_swapout() fails, the current code calls
ttm_resource_add_bulk_move() followed by ttm_resource_move_to_lru_tail()
to restore the resource's bulk_move membership.

However, ttm_resource_move_to_lru_tail() places the resource at the tail
of the LRU list which, relative to the walk cursor's hitch node (placed
immediately after the resource when it was yielded), puts the resource
*in front of the* the hitch. The next list_for_each_entry_continue() from
the hitch finds the same resource again, causing an infinite loop.

Fix by deferring del_bulk_move to the success path only.

On the success path, TTM_TT_FLAG_SWAPPED has just been set by
ttm_tt_swapout() but the resource is still tracked in the bulk_move range,
so ttm_resource_del_bulk_move()'s !ttm_resource_unevictable() guard would
incorrectly skip the removal. Introduce
ttm_resource_del_bulk_move_unevictable() which bypasses that guard.
Comment 1 Mauro Matteo Cascella 2026-06-25 13:01:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062438-CVE-2026-52965-b15c@gregkh/T