diff --git a/block/mirror.c b/block/mirror.c
index 98fc66eabfe7..85b781bc2169 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -160,18 +160,25 @@ static void coroutine_fn mirror_wait_on_conflicts(MirrorOp *self,
             if (ranges_overlap(self_start_chunk, self_nb_chunks,
                                op_start_chunk, op_nb_chunks))
             {
-                /*
-                 * If the operation is already (indirectly) waiting for us, or
-                 * will wait for us as soon as it wakes up, then just go on
-                 * (instead of producing a deadlock in the former case).
-                 */
-                if (op->waiting_for_op) {
-                    continue;
+                if (self) {
+                    /*
+                     * If the operation is already (indirectly) waiting for us,
+                     * or will wait for us as soon as it wakes up, then just go
+                     * on (instead of producing a deadlock in the former case).
+                     */
+                    if (op->waiting_for_op) {
+                        continue;
+                    }
+
+                    self->waiting_for_op = op;
                 }
 
-                self->waiting_for_op = op;
                 qemu_co_queue_wait(&op->waiting_requests, NULL);
-                self->waiting_for_op = NULL;
+
+                if (self) {
+                    self->waiting_for_op = NULL;
+                }
+
                 break;
             }
         }