Race against parent deletion in key_user_lookup()

[David Howells <dhowells@redhat.com>]

I looked at some of the oops reports against keyrings, I think the problem
is that the search isn't restarted after dropping the key_user_lock,
*p will still be NULL when we get back to try_again and look through the tree.

It looks like the intention was that the search start over from scratch.

Signed-off-by: Alexander Nyberg <alexn@dsv.su.se>
Signed-Off-By: David Howells <dhowells@redhat.com>

===== security/keys/key.c 1.5 vs edited =====
--- 1.5/security/keys/key.c	2005-01-21 06:02:10 +01:00
+++ edited/security/keys/key.c	2005-03-09 12:04:54 +01:00
@@ -57,9 +57,10 @@ struct key_user *key_user_lookup(uid_t u
 {
 	struct key_user *candidate = NULL, *user;
 	struct rb_node *parent = NULL;
-	struct rb_node **p = &key_user_tree.rb_node;
+	struct rb_node **p;
 
  try_again:
+	p = &key_user_tree.rb_node;
 	spin_lock(&key_user_lock);
 
 	/* search the tree for a user record with a matching UID */