unsigned i;
        int r = 0;
 
+       if (resv == NULL)
+               return -EINVAL;
+
        /* always sync to the exclusive fence */
        f = reservation_object_get_excl(resv);
        fence = f ? to_amdgpu_fence(f) : NULL;
        for (i = 0; i < flist->shared_count; ++i) {
                f = rcu_dereference_protected(flist->shared[i],
                                              reservation_object_held(resv));
-               fence = to_amdgpu_fence(f);
+               fence = f ? to_amdgpu_fence(f) : NULL;
                if (fence && fence->ring->adev == adev) {
                        if (fence->owner != owner ||
                            fence->owner == AMDGPU_FENCE_OWNER_UNDEFINED)
                                amdgpu_sync_fence(sync, fence);
-               } else {
+               } else if (f) {
                        r = fence_wait(f, true);
                        if (r)
                                break;