From: Eric W. Biederman <ebiederm@xmission.com>
Date: Wed, 13 May 2009 17:00:41 +0000 (+0000)
Subject: net: Fix bridgeing sysfs handling of rtnl_lock
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=af38f2989572704a846a5577b5ab3b1e2885cbfb;p=linux-beck.git

net: Fix bridgeing sysfs handling of rtnl_lock

Holding rtnl_lock when we are unregistering the sysfs files can
deadlock if we unconditionally take rtnl_lock in a sysfs file.  So fix
it with the now familiar patter of: rtnl_trylock and syscall_restart()

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 603d89248e71..ee4820aa1843 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -172,7 +172,8 @@ static ssize_t store_stp_state(struct device *d,
 	if (endp == buf)
 		return -EINVAL;
 
-	rtnl_lock();
+	if (!rtnl_trylock())
+		return restart_syscall();
 	br_stp_set_enabled(br, val);
 	rtnl_unlock();
 
diff --git a/net/bridge/br_sysfs_if.c b/net/bridge/br_sysfs_if.c
index 02b2d50cce4d..4a3cdf8f3813 100644
--- a/net/bridge/br_sysfs_if.c
+++ b/net/bridge/br_sysfs_if.c
@@ -189,7 +189,8 @@ static ssize_t brport_store(struct kobject * kobj,
 
 	val = simple_strtoul(buf, &endp, 0);
 	if (endp != buf) {
-		rtnl_lock();
+		if (!rtnl_trylock())
+			return restart_syscall();
 		if (p->dev && p->br && brport_attr->store) {
 			spin_lock_bh(&p->br->lock);
 			ret = brport_attr->store(p, val);