From patchwork Fri Oct 5 06:15:48 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gao feng X-Patchwork-Id: 1551211 X-Patchwork-Delegate: roland@digitalvampire.org Return-Path: X-Original-To: patchwork-linux-rdma@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork2.kernel.org (Postfix) with ESMTP id 77292DF24C for ; Fri, 5 Oct 2012 06:58:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752252Ab2JEG6O (ORCPT ); Fri, 5 Oct 2012 02:58:14 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:23140 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751963Ab2JEG5W (ORCPT ); Fri, 5 Oct 2012 02:57:22 -0400 X-IronPort-AV: E=Sophos;i="4.80,540,1344182400"; d="scan'208";a="5948857" Received: from unknown (HELO tang.cn.fujitsu.com) ([10.167.250.3]) by song.cn.fujitsu.com with ESMTP; 05 Oct 2012 14:14:27 +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 q956FngD028787; Fri, 5 Oct 2012 14:15:50 +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 2012100514154920-278071 ; Fri, 5 Oct 2012 14:15:49 +0800 From: Gao feng To: davem@davemloft.net Cc: eric.dumazet@gmail.com, steffen.klassert@secunet.com, pablo@netfilter.org, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, stephen.hemminger@vyatta.com, jengelh@inai.de, Gao feng Subject: [patch v4 1/2] netlink: add reference of module in netlink_dump_start Date: Fri, 5 Oct 2012 14:15:48 +0800 Message-Id: <1349417749-24869-1-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 2012/10/05 14:15:49, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/10/05 14:15:50, Serialize complete at 2012/10/05 14:15:50 Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@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 which the cb->dump belongs to. Thanks for all help from Stephen,Jan,Eric,Steffen and Pablo. Change From v3: change netlink_dump_start to inline,suggestion from Pablo and Eric. Change From v2: delete netlink_dump_done,and call module_put in netlink_dump and netlink_sock_destruct. Signed-off-by: Gao feng --- include/linux/netlink.h | 20 ++++++++++++++++---- net/netlink/af_netlink.c | 29 +++++++++++++++++++++-------- 2 files changed, 37 insertions(+), 12 deletions(-) diff --git a/include/linux/netlink.h b/include/linux/netlink.h index f80c56a..6d3af05 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -245,6 +245,8 @@ 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; @@ -262,14 +264,24 @@ __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int fla 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_start(struct sock *ssk, struct sk_buff *skb, - const struct nlmsghdr *nlh, - struct netlink_dump_control *control); +extern int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control); +static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control) +{ + if (!control->module) + control->module = THIS_MODULE; + + return __netlink_dump_start(ssk, skb, nlh, control); +} #endif /* __KERNEL__ */ diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 0f2e3ad..01e944a 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -169,6 +169,8 @@ static void netlink_sock_destruct(struct sock *sk) if (nlk->cb) { if (nlk->cb->done) nlk->cb->done(nlk->cb); + + module_put(nlk->cb->module); netlink_destroy_callback(nlk->cb); } @@ -1758,6 +1760,7 @@ static int netlink_dump(struct sock *sk) nlk->cb = NULL; mutex_unlock(nlk->cb_mutex); + module_put(cb->module); netlink_consume_callback(cb); return 0; @@ -1767,9 +1770,9 @@ errout_skb: return err; } -int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, - const struct nlmsghdr *nlh, - struct netlink_dump_control *control) +int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, + const struct nlmsghdr *nlh, + struct netlink_dump_control *control) { struct netlink_callback *cb; struct sock *sk; @@ -1784,6 +1787,7 @@ 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; @@ -1794,19 +1798,28 @@ 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 which cb->dump belongs 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) @@ -1817,7 +1830,7 @@ int netlink_dump_start(struct sock *ssk, struct sk_buff *skb, */ return -EINTR; } -EXPORT_SYMBOL(netlink_dump_start); +EXPORT_SYMBOL(__netlink_dump_start); void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err) {