Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-28T00:00:00 kernel: drm/amdkfd: Avoid double-unpin of DOORBELL/MMIO BOs on free 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-832

In the Linux kernel, the following vulnerability has been resolved: drm/amdkfd: Avoid double-unpin of DOORBELL/MMIO BOs on free amdgpu_amdkfd_gpuvm_free_memory_of_gpu() 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 ttm_bo_unpin() underflow warning: WARNING: CPU: 18 PID: 15066 at ttm/ttm_bo.c:650 amdttm_bo_unpin+0x6d/0x80 [amdttm] Workqueue: kfd_process_wq kfd_process_wq_release [amdgpu] RIP: 0010:amdttm_bo_unpin+0x6d/0x80 [amdttm] Call Trace: amdgpu_bo_unpin+0x1a/0x90 [amdgpu] amdgpu_amdkfd_gpuvm_unpin_bo+0x31/0xb0 [amdgpu] amdgpu_amdkfd_gpuvm_free_memory_of_gpu+0x3bf/0x460 [amdgpu] kfd_process_free_outstanding_kfd_bos+0xd4/0x170 [amdgpu] kfd_process_wq_release+0x109/0x1b0 [amdgpu] process_one_work+0x1e2/0x3b0 worker_thread+0x50/0x3a0 kthread+0xdd/0x100 ret_from_fork+0x29/0x50 Move the unpin after the mapped_to_gpu_memory check so it only happens once we are committed to freeing the BO. (cherry picked from commit 927c5b2defb9b09856444d94bebfd056a002bd75)

A flaw was found in the kernel's AMD GPU driver (drm/amdkfd). This vulnerability occurs when the driver attempts to unpin a memory buffer object (BO) twice during memory deallocation. A local attacker could exploit this double-unpin operation, leading to a memory management error. This issue can cause system instability or a denial of service (DoS).

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Out of support scope kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Fix deferred kernel Red Hat Enterprise Linux 8 Fix deferred kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-80618 https://nvd.nist.gov/vuln/detail/CVE-2026-80618 https://lore.kernel.org/linux-cve-announce/2026082835-CVE-2026-80618-5d17@gregkh/T