From: Wei Yongjun <yjwei@cn.fujitsu.com>
Date: Fri, 19 Dec 2008 03:35:10 +0000 (-0800)
Subject: net: Fix module refcount leak in kernel_accept()
X-Git-Tag: v2.6.28~14^2~1
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=1b08534e562dae7b084326f8aa8cc12a4c1b6593

net: Fix module refcount leak in kernel_accept()

The kernel_accept() does not hold the module refcount of newsock->ops->owner,
so we need __module_get(newsock->ops->owner) code after call kernel_accept()
by hand.
In sunrpc, the module refcount is missing to hold. So this cause kernel panic.

Used following script to reproduct:

while [ 1 ];
do
    mount -t nfs4 192.168.0.19:/ /mnt
    touch /mnt/file
    umount /mnt
    lsmod | grep ipv6
done

This patch fixed the problem by add __module_get(newsock->ops->owner) to
kernel_accept(). So we do not need to used __module_get(newsock->ops->owner)
in every place when used kernel_accept().

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c
index ba537fae0a4..ce68e046d96 100644
--- a/net/bluetooth/rfcomm/core.c
+++ b/net/bluetooth/rfcomm/core.c
@@ -1786,8 +1786,6 @@ static inline void rfcomm_accept_connection(struct rfcomm_session *s)
 	if (err < 0)
 		return;
 
-	__module_get(nsock->ops->owner);
-
 	/* Set our callbacks */
 	nsock->sk->sk_data_ready   = rfcomm_l2data_ready;
 	nsock->sk->sk_state_change = rfcomm_l2state_change;
diff --git a/net/socket.c b/net/socket.c
index 92764d83689..76ba80aeac1 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2307,6 +2307,7 @@ int kernel_accept(struct socket *sock, struct socket **newsock, int flags)
 	}
 
 	(*newsock)->ops = sock->ops;
+	__module_get((*newsock)->ops->owner);
 
 done:
 	return err;