From: ebiederm@xmission.com (Eric W. Biederman)
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH 1/2] net: Fix sysctl restarts...
Date: Fri, 19 Feb 2010 15:35:27 -0800 [thread overview]
Message-ID: <m1ocjksssg.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20100219.152954.39315470.davem@davemloft.net> (David Miller's message of "Fri\, 19 Feb 2010 15\:29\:54 -0800 \(PST\)")
David Miller <davem@davemloft.net> writes:
> From: ebiederm@xmission.com (Eric W. Biederman)
> Date: Fri, 19 Feb 2010 15:22:59 -0800
>
>>
>> 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 <ebiederm@xmission.com>
>
> What commit added this bug?
When we I fixed the deadlock that can happen if you write to forwarding
while removing the device. The deadlock was fixed, the restart worked
but I somehow missed the fact that proc_dointvec modifies state and so
defeated the change detection. *embarrassing*
commit 9b8adb5ea005fe73acd5dd58f9bd47eafa74c9d1
Author: Eric W. Biederman <ebiederm@xmission.com>
Date: Wed May 13 16:59:21 2009 +0000
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>
next prev parent reply other threads:[~2010-02-19 23:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-19 23:22 [PATCH 1/2] net: Fix sysctl restarts Eric W. Biederman
2010-02-19 23:23 ` [PATCH 2/2] net-sysfs: Use rtnl_trylock in wireless sysfs methods Eric W. Biederman
2010-02-19 23:29 ` [PATCH 1/2] net: Fix sysctl restarts David Miller
2010-02-19 23:35 ` Eric W. Biederman [this message]
2010-02-19 23:41 ` David Miller
2010-02-19 23:58 ` Eric W. Biederman
2010-02-20 0:02 ` David Miller
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