diff --git a/server/gc/fsck.c b/server/gc/fsck.c
index 8a40cbd..aa37858 100644
--- a/server/gc/fsck.c
+++ b/server/gc/fsck.c
@@ -582,7 +582,7 @@ out:
     }
     g_list_free (commit_list);
 
-    if (!repo->head) {
+    if (!repo || !repo->head) {
         seaf_warning("No available commits found for repo %.8s, can't be repaired.\n",
                      repo_id);
         seaf_repo_unref (repo);