diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 14ea47f954f5..6afcb054780d 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -597,6 +597,10 @@ static int z_erofs_map_blocks_ext(struct inode *inode,
 
 			if (la > map->m_la) {
 				r = mid;
+				if (la > lend) {
+					DBG_BUGON(1);
+					return -EFSCORRUPTED;
+				}
 				lend = la;
 			} else {
 				l = mid + 1;