Commit 7fa7cb71 authored Sep 27, 2010 by Eric Dumazet Committed by David S. Miller Sep 27, 2010

fib: use atomic_inc_not_zero() in fib_rules_lookup



It seems we dont use appropriate refcount increment in an
rcu_read_lock() protected section.

fib_rule_get() might increment a null refcount and bad things could
happen.

While fib_nl_delrule() respects an rcu grace period before calling
fib_rule_put(), fib_rules_cleanup_ops() calls fib_rule_put() without a
grace period.

Note : after this patch, we might avoid the synchronize_rcu() call done
in fib_nl_delrule()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 15fc1f70

net/core/fib_rules.c

+5 −3

Original line number	Original line	Diff line number	Diff line
	@@ -225,10 +225,12 @@ jumped:
	err = ops->action(rule, fl, flags, arg);		err = ops->action(rule, fl, flags, arg);

	if (err != -EAGAIN) {		if (err != -EAGAIN) {
	fib_rule_get(rule);		if (likely(atomic_inc_not_zero(&rule->refcnt))) {
	arg->rule = rule;		arg->rule = rule;
	goto out;		goto out;
	}		}
			break;
			}
	}		}

	err = -ESRCH;		err = -ESRCH;