1 files changed, 2 insertions, 0 deletions

diff --git a/fs/namei.c b/fs/namei.c
index b8433ebfae05..78f253cd2d4f 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1248,6 +1248,8 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
         int err;
         struct qstr this;
 
+        WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex));
+
         err = __lookup_one_len(name, &this, base, len);
         if (err)
                 return ERR_PTR(err);