From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH 1/2] net: Fix sysctl restarts... Date: Fri, 19 Feb 2010 15:22:59 -0800 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: To: David Miller Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:59009 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755745Ab0BSXXG (ORCPT ); Fri, 19 Feb 2010 18:23:06 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Yuck. It turns out that when we restart sysctls we were restarting with the values already changed. Which unfortunately meant that the second time through we thought there was no change and skipped all kinds of work, despite the fact that there was indeed a change. I have fixed this the simplest way possible by restoring the changed values when we restart the sysctl write. One of my coworkers spotted this bug when after disabling forwarding on an interface pings were still forwarded. Signed-off-by: Eric W. Biederman --- net/ipv4/devinet.c | 7 ++++++- net/ipv6/addrconf.c | 16 ++++++++++++++-- 2 files changed, 20 insertions(+), 3 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 014982b..51ca946 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1317,14 +1317,19 @@ static int devinet_sysctl_forward(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write && *valp != val) { struct net *net = ctl->extra2; if (valp != &IPV4_DEVCONF_DFLT(net, FORWARDING)) { - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *valp = val; + *ppos = pos; return restart_syscall(); + } if (valp == &IPV4_DEVCONF_ALL(net, FORWARDING)) { inet_forward_change(net); } else if (*valp) { diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index b0d4a4b..5bcf0d3 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -502,8 +502,11 @@ static int addrconf_fixup_forwarding(struct ctl_table *table, int *p, int old) if (p == &net->ipv6.devconf_dflt->forwarding) return 0; - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *p = old; return restart_syscall(); + } if (p == &net->ipv6.devconf_all->forwarding) { __s32 newf = net->ipv6.devconf_all->forwarding; @@ -4042,12 +4045,15 @@ int addrconf_sysctl_forward(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret; ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write) ret = addrconf_fixup_forwarding(ctl, valp, val); + if (ret) + *ppos = pos; return ret; } @@ -4089,8 +4095,11 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int old) if (p == &net->ipv6.devconf_dflt->disable_ipv6) return 0; - if (!rtnl_trylock()) + if (!rtnl_trylock()) { + /* Restore the original values before restarting */ + *p = old; return restart_syscall(); + } if (p == &net->ipv6.devconf_all->disable_ipv6) { __s32 newf = net->ipv6.devconf_all->disable_ipv6; @@ -4109,12 +4118,15 @@ int addrconf_sysctl_disable(ctl_table *ctl, int write, { int *valp = ctl->data; int val = *valp; + loff_t pos = *ppos; int ret; ret = proc_dointvec(ctl, write, buffer, lenp, ppos); if (write) ret = addrconf_disable_ipv6(ctl, valp, val); + if (ret) + *ppos = pos; return ret; } -- 1.6.5.2.143.g8cc62