From 3ed18d76d959e5cbfa5d70c8f7ba95476582a556 Mon Sep 17 00:00:00 2001 From: Robert Olsson Date: Thu, 21 May 2009 15:20:59 -0700 Subject: [PATCH] ipv4: Fix oops with FIB_TRIE It seems we can fix this by disabling preemption while we re-balance the trie. This is with the CONFIG_CLASSIC_RCU. It's been stress-tested at high loads continuesly taking a full BGP table up/down via iproute -batch. Note. fib_trie is not updated for CONFIG_PREEMPT_RCU Reported-by: Andrei Popa Signed-off-by: Robert Olsson Signed-off-by: David S. Miller --- net/ipv4/fib_trie.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c index ec0ae490f0b6..33c7c85dfe40 100644 --- a/net/ipv4/fib_trie.c +++ b/net/ipv4/fib_trie.c @@ -986,9 +986,12 @@ fib_find_node(struct trie *t, u32 key) static struct node *trie_rebalance(struct trie *t, struct tnode *tn) { int wasfull; - t_key cindex, key = tn->key; + t_key cindex, key; struct tnode *tp; + preempt_disable(); + key = tn->key; + while (tn != NULL && (tp = node_parent((struct node *)tn)) != NULL) { cindex = tkey_extract_bits(key, tp->pos, tp->bits); wasfull = tnode_full(tp, tnode_get_child(tp, cindex)); @@ -1007,6 +1010,7 @@ static struct node *trie_rebalance(struct trie *t, struct tnode *tn) if (IS_TNODE(tn)) tn = (struct tnode *)resize(t, (struct tnode *)tn); + preempt_enable(); return (struct node *)tn; } -- 2.20.1