[PATCH 2/1] Re: [BUG] fib_tries related Oops in 2.6.30

[Jarek Poplawski <jarkao2@gmail.com>]

ipv4: Fix fib_trie rebalancing, part 2

My previous patch, which explicitly delays freeing of tnodes by adding
them to the list to flushe them after the update is finished, isn't
strict enough. It treats exceptionally tnodes without parent, assuming
they are newly created, so "invisible" for the read side yet. But the
top tnode doesn't have parent as well, so we have to exclude all
exceptions (at least until a better way is found).

Reported-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
---

 net/ipv4/fib_trie.c |    9 ++-------
 1 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index d1a39b1..64395b0 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -391,13 +391,8 @@ static inline void tnode_free(struct tnode *tn)
 static void tnode_free_safe(struct tnode *tn)
 {
 	BUG_ON(IS_LEAF(tn));
-
-	if (node_parent((struct node *) tn)) {
-		tn->tnode_free = tnode_free_head;
-		tnode_free_head = tn;
-	} else {
-		tnode_free(tn);
-	}
+	tn->tnode_free = tnode_free_head;
+	tnode_free_head = tn;
 }
 
 static void tnode_free_flush(void)