From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next-2.6] net: sk_attach_filter() rcu fix Date: Mon, 27 Sep 2010 17:57:44 +0200 Message-ID: <1285603064.3017.42.camel@edumazet-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev , "Paul E. McKenney" To: David Miller Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:46258 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933161Ab0I0P5t (ORCPT ); Mon, 27 Sep 2010 11:57:49 -0400 Received: by fxm3 with SMTP id 3so1935822fxm.19 for ; Mon, 27 Sep 2010 08:57:48 -0700 (PDT) Sender: netdev-owner@vger.kernel.org List-ID: sk_attach_filter() is run with socket locked. Use the appropriate rcu_dereference_protected() instead of blocking BH, and rcu_dereference_bh(). There is no point adding BH prevention and memory barrier. Signed-off-by: Eric Dumazet --- net/core/filter.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 52b051f..93ac5d2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -638,10 +638,9 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) return err; } - rcu_read_lock_bh(); - old_fp = rcu_dereference_bh(sk->sk_filter); + old_fp = rcu_dereference_protected(sk->sk_filter, + sock_owned_by_user(sk)); rcu_assign_pointer(sk->sk_filter, fp); - rcu_read_unlock_bh(); if (old_fp) sk_filter_delayed_uncharge(sk, old_fp);