Commit 4cc5b44b authored Sep 01, 2017 by Eric Dumazet Committed by David S. Miller Sep 01, 2017

inetpeer: fix RCU lookup()



Excess of seafood or something happened while I cooked the commit
adding RB tree to inetpeer.

Of course, RCU rules need to be respected or bad things can happen.

In this particular loop, we need to read *pp once per iteration, not
twice.

Fixes: b145425f ("inetpeer: remove AVL implementation in favor of RB tree")
Reported-by: John Sperbeck <jsperbeck@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent bbd9644e

net/ipv4/inetpeer.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -102,15 +102,18 @@ static struct inet_peer lookup(const struct inetpeer_addr daddr,
		struct rb_node **parent_p,
		struct rb_node ***pp_p)
		{
		struct rb_node *pp, parent;
		struct rb_node *pp, parent, *next;
		struct inet_peer *p;

		pp = &base->rb_root.rb_node;
		parent = NULL;
		while (*pp) {
		while (1) {
		int cmp;

		parent = rcu_dereference_raw(*pp);
		next = rcu_dereference_raw(*pp);
		if (!next)
		break;
		parent = next;
		p = rb_entry(parent, struct inet_peer, rb_node);
		cmp = inetpeer_addr_cmp(daddr, &p->daddr);
		if (cmp == 0) {

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