linux-kernel - Re: Soft lockup on shutdown in nf_ct_iterate

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Date:	Sat, 24 Feb 2007 11:18:14 -0500
From:	Chuck Ebbert <cebbert@...hat.com>
To:	Patrick McHardy <kaber@...sh.net>
CC:	netfilter-devel@...ts.netfilter.org,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Soft lockup on shutdown in nf_ct_iterate_cleanup()

Patrick McHardy wrote:
> Chuck Ebbert wrote:
>> Chuck Ebbert wrote:
>>
>>> I was testing a 2.6.20 kernel and got a soft
>>> lockup on shutdown:
>>>
>>> _raw_write_lock+0x5a
>>> nf_ct_iterate_cleanup+0x3e
>>> kill_l3proto+0x0
>>> nf_conntrack_l3proto_unregister+0x85
>>> nf_conntrack_l3proto_ipv4_fini+0x1e
>>> sys_delete_module+0x18a
>>> remove_vma+0x45
>>> do_munmap+0x196
>>> syscall_call+0x7
>>
>> Happened three times in a row, trying to remove
>> netfilter modules.
> 
> Does it happen when you unload only nf_conntrack_ipv4, or do
> you need to unload other modules previously? Does it really
> lock up?
> 

It is the standard Fedora script "iptables" and it recursively
unloads all referring modules, then the base ones: ip_tables and
ip_conntrack. I can't tell which module it stopped on because
that computer is at home today. 

And yes, it really locks up until it's caught by the softlockup
watchdog. Has only happened on a uniprocessor i686 system so far,
but happens every time on shutdown.

> Please also send your config.

Standard Fedora 6 i686 config, updated for 2.6.20, not released yet.
I'll attach it.

View attachment "kernel-2.6.20-i686.config" of type "text/plain" (70785 bytes)