[PATCH] Fix do_path_lookup() to add the check for error in link_path_walk()

Fix do_path_lookup() to avoid accessing invalid dentry or inode when the
link_path_walk() has failed.  This should fix Bugme #5897.
Signed-off-by: Suzuki K P <suzuki@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/namei.c

@@ -1119,9 +1119,11 @@ static int fastcall do_path_lookup(int dfd, const char *name,
 	current->total_link_count = 0;
 	retval = link_path_walk(name, nd);
 out:
-	if (unlikely(current->audit_context
-		     && nd && nd->dentry && nd->dentry->d_inode))
+	if (likely(retval == 0)) {
+		if (unlikely(current->audit_context && nd && nd->dentry &&
+				nd->dentry->d_inode))
 		audit_inode(name, nd->dentry->d_inode, flags);
+	}
 	return retval;
 
 fput_unlock_fail: