diff --git a/sys/dev/drm/amd/amdgpu/amdgpu_sa.c b/sys/dev/drm/amd/amdgpu/amdgpu_sa.c
--- a/sys/dev/drm/amd/amdgpu/amdgpu_sa.c
+++ b/sys/dev/drm/amd/amdgpu/amdgpu_sa.c
@@ -79,8 +79,10 @@
 {
 	struct amdgpu_sa_bo *sa_bo, *tmp;
 
+	lockmgr(&sa_manager->wq.lock, LK_EXCLUSIVE);
 	if (sa_manager->bo == NULL) {
 		dev_err(adev->dev, "no bo for sa manager\n");
+		lockmgr(&sa_manager->wq.lock, LK_RELEASE);
 		return;
 	}
 
@@ -97,6 +99,7 @@
 
 	amdgpu_bo_free_kernel(&sa_manager->bo, (u64 *)&sa_manager->gpu_addr, &sa_manager->cpu_ptr);
 	sa_manager->size = 0;
+	lockmgr(&sa_manager->wq.lock, LK_RELEASE);
 }
 
 static void amdgpu_sa_bo_remove_locked(struct amdgpu_sa_bo *sa_bo)