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Commit 3ed18d76 authored by Robert Olsson's avatar Robert Olsson Committed by David S. Miller
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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: default avatarRobert Olsson <robert.olsson@its.uu.se>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 5b5f792a

net/ipv4/fib_trie.c

+5 −1
Original line number Diff line number Diff line
@@ -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;

}