Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755158Ab2JZASK (ORCPT ); Thu, 25 Oct 2012 20:18:10 -0400 Received: from mail.kernel.org ([198.145.19.201]:53848 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754475Ab2JZAIL (ORCPT ); Thu, 25 Oct 2012 20:08:11 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Gao feng , "David S. Miller" Subject: [ 63/85] netlink: add reference of module in netlink_dump_start Date: Thu, 25 Oct 2012 17:06:21 -0700 Message-Id: <20121026000037.452678502@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.2.421.g261b511 In-Reply-To: <20121026000031.107227138@linuxfoundation.org> References: <20121026000031.107227138@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4782 Lines: 173 3.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gao feng [ Upstream commit 6dc878a8ca39e93f70c42f3dd7260bde10c1e0f1 ] I get a panic when I use ss -a and rmmod inet_diag at the same time. It's because netlink_dump uses inet_diag_dump which belongs to module inet_diag. I search the codes and find many modules have the same problem. We need to add a reference to 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/netlink.h | 21 +++++++++++++++++---- net/netlink/af_netlink.c | 29 +++++++++++++++++++++-------- 2 files changed, 38 insertions(+), 12 deletions(-) --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -153,6 +153,7 @@ struct nlattr { #include #include +#include struct net; @@ -232,6 +233,8 @@ 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; @@ -249,14 +252,24 @@ __nlmsg_put(struct sk_buff *skb, u32 pid 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); +} #define NL_NONROOT_RECV 0x1 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -169,6 +169,8 @@ static void netlink_sock_destruct(struct if (nlk->cb) { if (nlk->cb->done) nlk->cb->done(nlk->cb); + + module_put(nlk->cb->module); netlink_destroy_callback(nlk->cb); } @@ -1760,6 +1762,7 @@ 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; @@ -1769,9 +1772,9 @@ 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; @@ -1786,6 +1789,7 @@ int netlink_dump_start(struct sock *ssk, 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 +1800,28 @@ int netlink_dump_start(struct sock *ssk, 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) @@ -1819,7 +1832,7 @@ int netlink_dump_start(struct sock *ssk, */ 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) { -- 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/