CVE-2026-99148

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: keep the eviction fence until the last handle is closed

amdgpu gem object close() detaches the user queue eviction fence from the BO before it checks bo va->ref count, so closing any handle of a BO removes the fence, even when the file still has another handle to the BO and the bo va with its GPU mappings stays. The BO can then be evicted without suspending the user queues of the file, which keep accessing it through mappings that are only marked for update.

Seen on navi31 with a SDMA user queue: a BO opened twice in the same file (GEM FLINK + GEM OPEN) loses its eviction fence when the second handle is closed (traced attach/detach of the fence):

attach bo=ffff8c78a6c84c00 GEM CLOSE handle=7 detach bo=ffff8c78a6c84c00

while handle 6 and the mapping are still in use.

Only detach the fence when the last reference to the bo va goes away, matching amdgpu gem object open(), which attaches it only when the bo va is created. With this the fence stays until the file is closed.

(cherry picked from commit 8387982f03d4026b7dc11b0b5e3118298eee4d6a)