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authorYunxiang Li <Yunxiang.Li@amd.com>2026-06-04 12:59:11 -0400
committerAlex Deucher <alexander.deucher@amd.com>2026-06-17 18:06:32 -0400
commit3f0cc1735273a57c5116710cf0202e12152f59cc (patch)
tree6bf5b8572f01b6cb993b3e8c10e24880160d0174
parent52d4ab1ca790a668cc8f2c27017138b1c467168c (diff)
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 <Yunxiang.Li@amd.com> Reviewed-by: Felix Kuehling <felix.kuehling@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit 927c5b2defb9b09856444d94bebfd056a002bd75)
-rw-r--r--drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index d54794e5b18b..35fe2c974699 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))