drm/amdkfd: amdkfd_free_gtt_mem clear the correct pointer

Pass pointer reference to amdgpu_bo_unref to clear the correct pointer,
otherwise amdgpu_bo_unref clear the local variable, the original pointer
not set to NULL, this could cause use-after-free bug.

Signed-off-by: Philip Yang <[e-mail]>
Reviewed-by: Felix Kuehling <[e-mail]>
Acked-by: Christian König <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c

···
 	return r;
 }
 
-void amdgpu_amdkfd_free_gtt_mem(struct amdgpu_device *adev, void *mem_obj)
+void amdgpu_amdkfd_free_gtt_mem(struct amdgpu_device *adev, void **mem_obj)
 {
-	struct amdgpu_bo *bo = (struct amdgpu_bo *) mem_obj;
+	struct amdgpu_bo **bo = (struct amdgpu_bo **) mem_obj;
 
-	amdgpu_bo_reserve(bo, true);
-	amdgpu_bo_kunmap(bo);
-	amdgpu_bo_unpin(bo);
-	amdgpu_bo_unreserve(bo);
-	amdgpu_bo_unref(&(bo));
+	amdgpu_bo_reserve(*bo, true);
+	amdgpu_bo_kunmap(*bo);
+	amdgpu_bo_unpin(*bo);
+	amdgpu_bo_unreserve(*bo);
+	amdgpu_bo_unref(bo);
 }
 
 int amdgpu_amdkfd_alloc_gws(struct amdgpu_device *adev, size_t size,

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h

···
 int amdgpu_amdkfd_alloc_gtt_mem(struct amdgpu_device *adev, size_t size,
 				void **mem_obj, uint64_t *gpu_addr,
 				void **cpu_ptr, bool mqd_gfx9);
-void amdgpu_amdkfd_free_gtt_mem(struct amdgpu_device *adev, void *mem_obj);
+void amdgpu_amdkfd_free_gtt_mem(struct amdgpu_device *adev, void **mem_obj);
 int amdgpu_amdkfd_alloc_gws(struct amdgpu_device *adev, size_t size,
 				void **mem_obj);
 void amdgpu_amdkfd_free_gws(struct amdgpu_device *adev, void *mem_obj);

drivers/gpu/drm/amd/amdkfd/kfd_chardev.c

···
 
 err_create_queue:
 	if (wptr_bo)
-		amdgpu_amdkfd_free_gtt_mem(dev->adev, wptr_bo);
+		amdgpu_amdkfd_free_gtt_mem(dev->adev, (void **)&wptr_bo);
 err_wptr_map_gart:
 err_bind_process:
 err_pdd:

drivers/gpu/drm/amd/amdkfd/kfd_device.c

···
 kfd_doorbell_error:
 	kfd_gtt_sa_fini(kfd);
 kfd_gtt_sa_init_error:
-	amdgpu_amdkfd_free_gtt_mem(kfd->adev, kfd->gtt_mem);
+	amdgpu_amdkfd_free_gtt_mem(kfd->adev, &kfd->gtt_mem);
 alloc_gtt_mem_failure:
 	dev_err(kfd_device,
 		"device %x:%x NOT added due to errors\n",
···
 		kfd_doorbell_fini(kfd);
 		ida_destroy(&kfd->doorbell_ida);
 		kfd_gtt_sa_fini(kfd);
-		amdgpu_amdkfd_free_gtt_mem(kfd->adev, kfd->gtt_mem);
+		amdgpu_amdkfd_free_gtt_mem(kfd->adev, &kfd->gtt_mem);
 	}
 
 	kfree(kfd);

drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c

···
 {
 	WARN(!mqd, "No hiq sdma mqd trunk to free");
 
-	amdgpu_amdkfd_free_gtt_mem(dev->adev, mqd->gtt_mem);
+	amdgpu_amdkfd_free_gtt_mem(dev->adev, &mqd->gtt_mem);
 }
 
 void device_queue_manager_uninit(struct device_queue_manager *dqm)

drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager.c

···
 	      struct kfd_mem_obj *mqd_mem_obj)
 {
 	if (mqd_mem_obj->gtt_mem) {
-		amdgpu_amdkfd_free_gtt_mem(mm->dev->adev, mqd_mem_obj->gtt_mem);
+		amdgpu_amdkfd_free_gtt_mem(mm->dev->adev, &mqd_mem_obj->gtt_mem);
 		kfree(mqd_mem_obj);
 	} else {
 		kfd_gtt_sa_free(mm->dev, mqd_mem_obj);

drivers/gpu/drm/amd/amdkfd/kfd_process.c

···
 
 		if (pdd->dev->kfd->shared_resources.enable_mes)
 			amdgpu_amdkfd_free_gtt_mem(pdd->dev->adev,
-						   pdd->proc_ctx_bo);
+						   &pdd->proc_ctx_bo);
 		/*
 		 * before destroying pdd, make sure to report availability
 		 * for auto suspend

drivers/gpu/drm/amd/amdkfd/kfd_process_queue_manager.c

···
 	}
 
 	if (dev->kfd->shared_resources.enable_mes) {
-		amdgpu_amdkfd_free_gtt_mem(dev->adev, pqn->q->gang_ctx_bo);
+		amdgpu_amdkfd_free_gtt_mem(dev->adev, &pqn->q->gang_ctx_bo);
 		if (pqn->q->wptr_bo)
-			amdgpu_amdkfd_free_gtt_mem(dev->adev, pqn->q->wptr_bo);
+			amdgpu_amdkfd_free_gtt_mem(dev->adev, (void **)&pqn->q->wptr_bo);
 	}
 }