security: testing the wrong variable in create_by_name()

There is a typo here.  We should be testing "*dentry" instead of
"dentry".  If "*dentry" is an ERR_PTR, it gets dereferenced in either
mkdir() or create() which would cause an OOPs.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: James Morris <jmorris@namei.org>

security/inode.c

@@ -161,13 +161,13 @@ static int create_by_name(const char *name, mode_t mode,
 
 	mutex_lock(&parent->d_inode->i_mutex);
 	*dentry = lookup_one_len(name, parent, strlen(name));
-	if (!IS_ERR(dentry)) {
+	if (!IS_ERR(*dentry)) {
 		if ((mode & S_IFMT) == S_IFDIR)
 			error = mkdir(parent->d_inode, *dentry, mode);
 		else
 			error = create(parent->d_inode, *dentry, mode);
 	} else
-		error = PTR_ERR(dentry);
+		error = PTR_ERR(*dentry);
 	mutex_unlock(&parent->d_inode->i_mutex);
 
 	return error;