ip_conntrack related slab error (Re: Fw: Re: 2.6.16-rc1-mm3)

[Harald Welte <laforge@netfilter.org>]

> Begin forwarded message:
> 
> Date: Sat, 28 Jan 2006 00:47:06 +1300
> From: Reuben Farrelly <reuben-lkml@reub.net>
> To: Andrew Morton <akpm@osdl.org>
> Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org
> Subject: Re: 2.6.16-rc1-mm3
> 
> Just triggered this one, which had a fairly bad effect on connectivity to the box:
> 
> i2c /dev entries driver
> slab error in kmem_cache_destroy(): cache `ip_conntrack': Can't free all objects
>   [<b010412b>] show_trace+0xd/0xf
>   [<b01041cc>] dump_stack+0x17/0x19
>   [<b0155d04>] kmem_cache_destroy+0x9b/0x1a9
>   [<f0ebf701>] ip_conntrack_cleanup+0x5d/0x10e [ip_conntrack]
>   [<f0ebe31e>] init_or_cleanup+0x1f8/0x283 [ip_conntrack]
>   [<f0ec2c4e>] fini+0xa/0x66 [ip_conntrack]
>   [<b0136d06>] sys_delete_module+0x161/0x1fb
>   [<b0102b3f>] sysenter_past_esp+0x54/0x75
> Removing netfilter NETLINK layer.
> [root@tornado log]#
> 
> I was just reading IMAP mail at the time, ie same as I'd been doing for an hour 
> or two beforehand and not altering config of the box in any way.  I was able to 
> log on via console but lost all network connectivity and had to reboot :(

The codepath you see in that backtrace is only hit during load or
removal of the 'ip_conntrack' module.  While this certainly still should
not oops, your description of 'not doing anything but IMAP reading' is
certainly not true.  

Could you please describe what actually happened when that bug happened?
It looks to me that you were unloading ip_conntrack_netlink.ko followed
by ip_conntrack.ko.

> Generic details such as .config is at http://www.reub.net/files/kernel/

You don't have permission to access /files/kernel/ on this server.

-- 
- Harald Welte <laforge@netfilter.org>                 http://netfilter.org/
============================================================================
  "Fragmentation is like classful addressing -- an interesting early
   architectural error that shows how much experimentation was going
   on while IP was being designed."                    -- Paul Vixie

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