From 9b8adb5ea005fe73acd5dd58f9bd47eafa74c9d1 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 13 May 2009 16:59:21 +0000 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- net/ipv4/devinet.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 126bb911880f..3863c3a4223f 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -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) {