CVE-2026-80618

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

drm/amdkfd: Avoid double-unpin of DOORBELL/MMIO BOs on free

amdgpuamdkfdgpuvmfreememoryofgpu() unpinned DOORBELL and MMIO remap BOs (which are pinned at allocation time) before checking whether the BO is still mapped to the GPU. When the BO is still mapped, the function returns -EBUSY and leaves the BO alive, but it has already been unpinned. The BO is then unpinned again when it is finally freed during process teardown, triggering a ttmbounpin() underflow warning:

WARNING: CPU: 18 PID: 15066 at ttm/ttmbo.c:650 amdttmbounpin+0x6d/0x80 [amdttm] Workqueue: kfdprocesswq kfdprocesswqrelease [amdgpu] RIP: 0010:amdttmbounpin+0x6d/0x80 [amdttm] Call Trace: amdgpubounpin+0x1a/0x90 [amdgpu] amdgpuamdkfdgpuvmunpinbo+0x31/0xb0 [amdgpu] amdgpuamdkfdgpuvmfreememoryofgpu+0x3bf/0x460 [amdgpu] kfdprocessfreeoutstandingkfdbos+0xd4/0x170 [amdgpu] kfdprocesswqrelease+0x109/0x1b0 [amdgpu] processonework+0x1e2/0x3b0 workerthread+0x50/0x3a0 kthread+0xdd/0x100 retfrom_fork+0x29/0x50

Move the unpin after the mappedtogpu_memory check so it only happens once we are committed to freeing the BO.

(cherry picked from commit 927c5b2defb9b09856444d94bebfd056a002bd75)