From patchwork Wed Sep 26 08:41:18 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gao feng X-Patchwork-Id: 187004 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 082822C007F for ; Wed, 26 Sep 2012 18:46:57 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754357Ab2IZIqr (ORCPT ); Wed, 26 Sep 2012 04:46:47 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:31054 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754062Ab2IZIqV (ORCPT ); Wed, 26 Sep 2012 04:46:21 -0400 X-IronPort-AV: E=Sophos;i="4.80,489,1344182400"; d="scan'208";a="5920149" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 26 Sep 2012 16:44:55 +0800 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id q8Q8fQrr015163; Wed, 26 Sep 2012 16:41:27 +0800 Received: from Donkey.fnst.cn.fujitsu.com ([10.167.225.206]) by fnstmail02.fnst.cn.fujitsu.com (Lotus Domino Release 8.5.3) with ESMTP id 2012092616414022-82947 ; Wed, 26 Sep 2012 16:41:40 +0800 From: Gao feng To: davem@davemloft.net, eric.dumazet@gmail.com, steffen.klassert@secunet.com Cc: netfilter-devel@vger.kernel.org, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, linux-crypto@vger.kernel.org, pablo@netfilter.org, stephen.hemminger@vyatta.com, jengelh@inai.de, Gao feng Subject: [patch v2 01/11] netlink: add reference of module in netlink_dump_start Date: Wed, 26 Sep 2012 16:41:18 +0800 Message-Id: <1348648888-24943-1-git-send-email-gaofeng@cn.fujitsu.com> X-Mailer: git-send-email 1.7.7.6 X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/26 16:41:40, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/09/26 16:41:45, Serialize complete at 2012/09/26 16:41:45 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org I get a panic when I use ss -a and rmmod inet_diag at the same time. it's because netlink_dump use inet_diag_dump witch function belongs to module inet_diag. I search the codes and find many modules have the same problem. We need add reference of the module witch the cb->dump belongs to. Thanks for all help from Stephen,Jan,Eric and Steffen. Signed-off-by: Gao feng --- include/linux/netlink.h | 6 +++++- net/netlink/af_netlink.c | 25 +++++++++++++++++++++---- 2 files changed, 26 insertions(+), 5 deletions(-) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index f74dd13..381f7d6 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -232,6 +232,8 @@ struct netlink_callback { struct netlink_callback *cb); int (*done)(struct netlink_callback *cb); void *data; + /* the module that dump function belong to */ + struct module *module; u16 family; u16 min_dump_alloc; unsigned int prev_seq, seq; @@ -249,11 +251,13 @@ __nlmsg_put(struct sk_buff *skb, u32 pid, u32 seq, int type, int len, int flags) struct netlink_dump_control { int (*dump)(struct sk_buff *skb, struct netlink_callback *); - int (*done)(struct netlink_callback*); + int (*done)(struct netlink_callback *); void *data; + struct module *module; u16 min_dump_alloc; }; +extern int netlink_dump_done(struct netlink_callback *cb); extern int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, const struct nlmsghdr *nlh, struct netlink_dump_control *control); diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 5270238..3190dae 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1769,6 +1769,13 @@ errout_skb: return err; } +int netlink_dump_done(struct netlink_callback *cb) +{ + module_put(cb->module); + return 0; +} +EXPORT_SYMBOL(netlink_dump_done); + int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, const struct nlmsghdr *nlh, struct netlink_dump_control *control) @@ -1786,6 +1793,7 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, cb->done = control->done; cb->nlh = nlh; cb->data = control->data; + cb->module = control->module; cb->min_dump_alloc = control->min_dump_alloc; atomic_inc(&skb->users); cb->skb = skb; @@ -1796,19 +1804,28 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, return -ECONNREFUSED; } nlk = nlk_sk(sk); - /* A dump is in progress... */ + mutex_lock(nlk->cb_mutex); + /* A dump is in progress... */ if (nlk->cb) { mutex_unlock(nlk->cb_mutex); netlink_destroy_callback(cb); - sock_put(sk); - return -EBUSY; + ret = -EBUSY; + goto out; + } + /* add reference of module witch cb->dump belong to */ + if (!try_module_get(cb->module)) { + mutex_unlock(nlk->cb_mutex); + netlink_destroy_callback(cb); + ret = -EPROTONOSUPPORT; + goto out; } + nlk->cb = cb; mutex_unlock(nlk->cb_mutex); ret = netlink_dump(sk); - +out: sock_put(sk); if (ret)