From a898def29e4119bc01ebe7ca97423181f4c0ea2d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 22 Feb 2010 17:04:49 -0800 Subject: net: Add checking to rcu_dereference() primitives Update rcu_dereference() primitives to use new lockdep-based checking. The rcu_dereference() in __in6_dev_get() may be protected either by rcu_read_lock() or RTNL, per Eric Dumazet. The rcu_dereference() in __sk_free() is protected by the fact that it is never reached if an update could change it. Check for this by using rcu_dereference_check() to verify that the struct sock's ->sk_wmem_alloc counter is zero. Acked-by: Eric Dumazet Acked-by: David S. Miller Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-5-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- net/core/sock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/core/sock.c') diff --git a/net/core/sock.c b/net/core/sock.c index e1f6f225f012..305cba401ae6 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1073,7 +1073,8 @@ static void __sk_free(struct sock *sk) if (sk->sk_destruct) sk->sk_destruct(sk); - filter = rcu_dereference(sk->sk_filter); + filter = rcu_dereference_check(sk->sk_filter, + atomic_read(&sk->sk_wmem_alloc) == 0); if (filter) { sk_filter_uncharge(sk, filter); rcu_assign_pointer(sk->sk_filter, NULL); -- cgit v1.2.3