Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964899AbbGVL4u (ORCPT ); Wed, 22 Jul 2015 07:56:50 -0400 Received: from www62.your-server.de ([213.133.104.62]:53189 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933918AbbGVL4s (ORCPT ); Wed, 22 Jul 2015 07:56:48 -0400 Message-ID: <55AF84FC.2070502@iogearbox.net> Date: Wed, 22 Jul 2015 13:56:44 +0200 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: Konstantin Khlebnikov CC: netdev@vger.kernel.org, "David S. Miller" , Tejun Heo , cgroups@vger.kernel.org, Li Zefan , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] cgroup: net_cls: fix false-positive "suspicious RCU usage" References: <20150721164629.18385.14538.stgit@buzz> <20150722092320.30663.86742.stgit@buzz> In-Reply-To: <20150722092320.30663.86742.stgit@buzz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1276 Lines: 31 On 07/22/2015 11:23 AM, Konstantin Khlebnikov wrote: > In dev_queue_xmit() net_cls protected with rcu-bh. ... > Signed-off-by: Konstantin Khlebnikov > --- > net/core/netclassid_cgroup.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/core/netclassid_cgroup.c b/net/core/netclassid_cgroup.c > index 1f2a126f4ffa..6441f47b1a8f 100644 > --- a/net/core/netclassid_cgroup.c > +++ b/net/core/netclassid_cgroup.c > @@ -23,7 +23,8 @@ static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state > > struct cgroup_cls_state *task_cls_state(struct task_struct *p) > { > - return css_cls_state(task_css(p, net_cls_cgrp_id)); > + return css_cls_state(task_css_check(p, net_cls_cgrp_id, > + rcu_read_lock_bh_held())); Did you also check that after your patch this doesn't trigger on ingress either? There, this code path could be invoked under rcu_read_lock(). So, perhaps you need to check for both. > } > EXPORT_SYMBOL_GPL(task_cls_state); -- 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/