-@@ -330,9 +342,11 @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,
+@@ -246,6 +258,8 @@ static void backup_abort(BlockJob *job)
+ static void backup_clean(BlockJob *job)
+ {
+ BackupBlockJob *s = container_of(job, BackupBlockJob, common);
++ if (!s->target)
++ return;
+ assert(s->target);
+ blk_unref(s->target);
+ s->target = NULL;
+@@ -330,9 +344,11 @@ static BlockErrorAction backup_error_action(BackupBlockJob *job,