From: Yunxiang Li Date: Thu, 4 Jun 2026 16:59:11 +0000 (-0400) Subject: drm/amdkfd: Avoid double-unpin of DOORBELL/MMIO BOs on free X-Git-Tag: v7.2-rc1~10^2~1^2~32 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3f0cc1735273a57c5116710cf0202e12152f59cc;p=thirdparty%2Fkernel%2Flinux.git 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. Fixes: d25e35bc26c3 ("drm/amdgpu: Pin MMIO/DOORBELL BO's in GTT domain") Signed-off-by: Yunxiang Li Reviewed-by: Felix Kuehling Signed-off-by: Alex Deucher (cherry picked from commit 927c5b2defb9b09856444d94bebfd056a002bd75) --- diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c index d54794e5b18bf..35fe2c9746991 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c @@ -1914,13 +1914,6 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu( mutex_lock(&mem->lock); - /* Unpin MMIO/DOORBELL BO's that were pinned during allocation */ - if (mem->alloc_flags & - (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL | - KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) { - amdgpu_amdkfd_gpuvm_unpin_bo(mem->bo); - } - mapped_to_gpu_memory = mem->mapped_to_gpu_memory; is_imported = mem->is_imported; mutex_unlock(&mem->lock); @@ -1934,6 +1927,15 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu( return -EBUSY; } + /* At this point the BO is guaranteed to be freed, so unpin the + * MMIO/DOORBELL BOs that were pinned during allocation. + */ + if (mem->alloc_flags & + (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL | + KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP)) { + amdgpu_amdkfd_gpuvm_unpin_bo(mem->bo); + } + /* Make sure restore workers don't access the BO any more */ mutex_lock(&process_info->lock); if (!list_empty(&mem->validate_list))