From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gao feng Subject: [PATCH] inet_diag: fix panic when unload inet_diag Date: Tue, 25 Sep 2012 10:48:30 +0800 Message-ID: <1348541310-31913-1-git-send-email-gaofeng@cn.fujitsu.com> Cc: stephen.hemminger@vyatta.com, jengelh@inai.de, eric.dumazet@gmail.com, kuznet@ms2.inr.ac.ru, netdev@vger.kernel.org, Gao feng To: davem@davemloft.net Return-path: Received: from cn.fujitsu.com ([222.73.24.84]:11493 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752407Ab2IYDAN (ORCPT ); Mon, 24 Sep 2012 23:00:13 -0400 Sender: netdev-owner@vger.kernel.org List-ID: when inet_diag being compiled as module, inet_diag_handler_dump set netlink_dump_control.dump to inet_diag_dump,so if module inet_diag is unloaded,netlink will still try to call this function in netlink_dump. this will cause kernel panic. fix this by adding a reference of inet_diag module before setting netlink_callback, and release this reference in netlink_callback.done. Thanks for all help from Stephen,Jan and Eric. Signed-off-by: Gao feng --- net/ipv4/inet_diag.c | 46 ++++++++++++++++++++++++++++++++++++++++++++-- 1 files changed, 44 insertions(+), 2 deletions(-) diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c index 570e61f..e573090 100644 --- a/net/ipv4/inet_diag.c +++ b/net/ipv4/inet_diag.c @@ -903,6 +903,12 @@ static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) return __inet_diag_dump(skb, cb, nlmsg_data(cb->nlh), bc); } +static int inet_diag_done(struct netlink_callback *cb) +{ + module_put(THIS_MODULE); + return 0; +} + static inline int inet_diag_type2proto(int type) { switch (type) { @@ -972,8 +978,26 @@ static int inet_diag_rcv_msg_compat(struct sk_buff *skb, struct nlmsghdr *nlh) { struct netlink_dump_control c = { .dump = inet_diag_dump_compat, + .done = inet_diag_done, }; - return netlink_dump_start(net->diag_nlsk, skb, nlh, &c); + int err; + /* + * netlink_dump will call inet_diag_dump_compat, + * so we need a reference of THIS_MODULE. + */ + if (!try_module_get(THIS_MODULE)) + return -EPROTONOSUPPORT; + + err = netlink_dump_start(net->diag_nlsk, skb, nlh, &c); + + if ((err != -EINTR) && (err != -ENOBUFS)) { + /* + * netlink_callback set failed, release the + * referenct of THIS_MODULE. + */ + module_put(THIS_MODULE); + } + return err; } } @@ -1001,8 +1025,26 @@ static int inet_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h) { struct netlink_dump_control c = { .dump = inet_diag_dump, + .done = inet_diag_done, }; - return netlink_dump_start(net->diag_nlsk, skb, h, &c); + int err; + /* + * netlink_dump will call inet_diag_dump, + * so we need a reference of THIS_MODULE. + */ + if (!try_module_get(THIS_MODULE)) + return -EPROTONOSUPPORT; + + err = netlink_dump_start(net->diag_nlsk, skb, h, &c); + + if ((err != -EINTR) && (err != -ENOBUFS)) { + /* + * netlink_callback set failed, release the + * referenct of THIS_MODULE. + */ + module_put(THIS_MODULE); + } + return err; } } -- 1.7.7