diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index a0da2b0..54ca4bc 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -130,8 +130,10 @@
 
 		/* look it up */
 		parent_dentry = dentry;
+		mutex_lock(&parent_dentry->d_inode->i_mutex);
 		dentry = lookup_one_len_kern(cur->s_name, parent_dentry,
 					     strlen(cur->s_name));
+		mutex_unlock(&parent_dentry->d_inode->i_mutex);
 		dput(parent_dentry);
 
 		if (IS_ERR(dentry)) {