Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754207Ab2HMWox (ORCPT ); Mon, 13 Aug 2012 18:44:53 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:44129 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753416Ab2HMWov (ORCPT ); Mon, 13 Aug 2012 18:44:51 -0400 From: Denis Efremov To: Pablo Neira Ayuso Cc: Denis Efremov , Patrick McHardy , netfilter-devel@vger.kernel.org, netfilter@vger.kernel.org, coreteam@netfilter.org, linux-kernel@vger.kernel.org, ldv-project@ispras.ru Subject: [PATCH] [NETFILTER] bridge: rcu_deref outside read-lock section Date: Tue, 14 Aug 2012 02:47:42 +0400 Message-Id: <1344898062-23633-1-git-send-email-yefremov.denis@gmail.com> X-Mailer: git-send-email 1.7.7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 50 As it noted in the comment before the br_handle_frame_finish function, this function should be called under rcu_read_lock. The problem callgraph: br_dev_xmit -> br_nf_pre_routing_finish_bridge_slow -> -> br_handle_frame_finish -> br_port_get_rcu -> rcu_dereference And in this case there is no read-lock section. I have put lock/unlock in br_nf_pre_routing_finish_bridge_slow, as the only function that calls it(for now) - is br_dev_xmit. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Denis Efremov --- include/linux/netfilter_bridge.h | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/include/linux/netfilter_bridge.h b/include/linux/netfilter_bridge.h index 31d2844..ceb048e 100644 --- a/include/linux/netfilter_bridge.h +++ b/include/linux/netfilter_bridge.h @@ -79,6 +79,7 @@ extern int br_handle_frame_finish(struct sk_buff *skb); /* Only used in br_device.c */ static inline int br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb) { + int res; struct nf_bridge_info *nf_bridge = skb->nf_bridge; skb_pull(skb, ETH_HLEN); @@ -86,7 +87,10 @@ static inline int br_nf_pre_routing_finish_bridge_slow(struct sk_buff *skb) skb_copy_to_linear_data_offset(skb, -(ETH_HLEN-ETH_ALEN), skb->nf_bridge->data, ETH_HLEN-ETH_ALEN); skb->dev = nf_bridge->physindev; - return br_handle_frame_finish(skb); + rcu_read_lock(); + res = br_handle_frame_finish(skb); + rcu_read_unlock(); + return res; } /* This is called by the IP fragmenting code and it ensures there is -- 1.7.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/