From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next-2.6] net: fix a lockdep rcu warning in __sk_dst_set() Date: Tue, 27 Apr 2010 08:40:43 +0200 Message-ID: <1272350443.4861.9.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev To: David Miller Return-path: Received: from mail-bw0-f219.google.com ([209.85.218.219]:48625 "EHLO mail-bw0-f219.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750830Ab0D0Gkt (ORCPT ); Tue, 27 Apr 2010 02:40:49 -0400 Received: by bwz19 with SMTP id 19so158535bwz.21 for ; Mon, 26 Apr 2010 23:40:47 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: __sk_dst_set() might be called while no state can be integrated in a rcu_dereference_check() condition. So use rcu_dereference_raw() to shutup lockdep warnings (if CONFIG_PROVE_RCU is set) Signed-off-by: Eric Dumazet --- diff --git a/include/net/sock.h b/include/net/sock.h index 86a8ca1..94dbdbc 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1236,8 +1236,11 @@ __sk_dst_set(struct sock *sk, struct dst_entry *dst) struct dst_entry *old_dst; sk_tx_queue_clear(sk); - old_dst = rcu_dereference_check(sk->sk_dst_cache, - lockdep_is_held(&sk->sk_dst_lock)); + /* + * This can be called while sk is owned by the caller only, + * with no state that can be checked in a rcu_dereference_check() cond + */ + old_dst = rcu_dereference_raw(sk->sk_dst_cache); rcu_assign_pointer(sk->sk_dst_cache, dst); dst_release(old_dst); }