net: Fix devinet_sysctl_forward

sysctls are unregistered with the rntl_lock held making
it unsafe to unconditionally grab the the rtnl_lock.  Instead
we need to call rtnl_trylock and restart the system call
if we can not grab it.  Otherwise we could deadlock at unregistration
time.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric W. Biederman 2009-05-13 16:59:21 +00:00 committed by David S. Miller
parent 5007392d85
commit 9b8adb5ea0

View File

@ -1347,7 +1347,8 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write,
struct net *net = ctl->extra2;
if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) {
rtnl_lock();
if (!rtnl_trylock())
return restart_syscall();
if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) {
inet_forward_change(net);
} else if (*valp) {