Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755148Ab2BAGxF (ORCPT ); Wed, 1 Feb 2012 01:53:05 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:60905 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1755128Ab2BAGxD (ORCPT ); Wed, 1 Feb 2012 01:53:03 -0500 Message-ID: <4F28E1F2.70805@cn.fujitsu.com> Date: Wed, 01 Feb 2012 14:55:46 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: David Miller CC: netdev , LKML , Cgroups , Neil Horman Subject: [PATCH 3/6] netprio_cgroup: fix wrong memory access when NETPRIO_CGROUP=m References: <4F28E1D1.900@cn.fujitsu.com> In-Reply-To: <4F28E1D1.900@cn.fujitsu.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-01 14:51:39, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2012-02-01 14:51:40, Serialize complete at 2012-02-01 14:51:40 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2799 Lines: 103 When the netprio_cgroup module is not loaded, net_prio_subsys_id is -1, and so sock_update_prioidx() accesses cgroup_subsys array with negative index subsys[-1]. Make the code resembles cls_cgroup code, which is bug free. Signed-off-by: Li Zefan --- include/net/netprio_cgroup.h | 48 +++++++++++++++++++++++++++++++++++------- net/core/sock.c | 7 +---- 2 files changed, 42 insertions(+), 13 deletions(-) diff --git a/include/net/netprio_cgroup.h b/include/net/netprio_cgroup.h index 7b2d431..d58fdec 100644 --- a/include/net/netprio_cgroup.h +++ b/include/net/netprio_cgroup.h @@ -37,19 +37,51 @@ extern int net_prio_subsys_id; extern void sock_update_netprioidx(struct sock *sk); -static inline struct cgroup_netprio_state - *task_netprio_state(struct task_struct *p) +#if IS_BUILTIN(CONFIG_NETPRIO_CGROUP) + +static inline u32 task_netprioidx(struct task_struct *p) { -#if IS_ENABLED(CONFIG_NETPRIO_CGROUP) - return container_of(task_subsys_state(p, net_prio_subsys_id), - struct cgroup_netprio_state, css); -#else - return NULL; -#endif + struct cgroup_netprio_state *state; + u32 idx; + + rcu_read_lock(); + state = container_of(task_subsys_state(p, net_prio_subsys_id), + struct cgroup_netprio_state, css); + idx = state->prioidx; + rcu_read_unlock(); + return idx; +} + +#elif IS_MODULE(CONFIG_NETPRIO_CGROUP) + +static inline u32 task_netprioidx(struct task_struct *p) +{ + struct cgroup_netprio_state *state; + int subsys_id; + u32 idx = 0; + + rcu_read_lock(); + subsys_id = rcu_dereference_index_check(net_prio_subsys_id, + rcu_read_lock_held()); + if (subsys_id >= 0) { + state = container_of(task_subsys_state(p, subsys_id), + struct cgroup_netprio_state, css); + idx = state->prioidx; + } + rcu_read_unlock(); + return idx; } #else +static inline u32 task_netprioidx(struct task_struct *p) +{ + return 0; +} + +#endif /* CONFIG_NETPRIO_CGROUP */ + +#else #define sock_update_netprioidx(sk) #endif diff --git a/net/core/sock.c b/net/core/sock.c index 3e81fd2..02f8dfe 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1171,13 +1171,10 @@ EXPORT_SYMBOL(sock_update_classid); void sock_update_netprioidx(struct sock *sk) { - struct cgroup_netprio_state *state; if (in_interrupt()) return; - rcu_read_lock(); - state = task_netprio_state(current); - sk->sk_cgrp_prioidx = state ? state->prioidx : 0; - rcu_read_unlock(); + + sk->sk_cgrp_prioidx = task_netprioidx(current); } EXPORT_SYMBOL_GPL(sock_update_netprioidx); #endif -- 1.7.3.1 -- 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/