From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: BUG: soft lockup detected on CPU#0! (2.6.18.2 plus hacks)
Date: Wed, 10 Jan 2007 23:40:35 -0800 (PST)
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From: Jarek Poplawski <jarkao2@o2.pl>
Date: Thu, 11 Jan 2007 08:24:28 +0100

> Yesterday I did what I should do earlier - checked
> this simple way, with printk, and now I have no doubts
> it's a bug: if you add or remove vlan devices with
> vconfig, register_vlan_device and unregister_vlan_dev
> are called by ioctl and they use and change rcu
> procetded data without preemption disabled so vlan
> rcu hash lists could become corrupted or find results
> could be wrong.

Those two operations do their modifications and changes under the RTNL
semaphore, via rtnl_lock() and rtnl_unlock() which guarentees that no
other modifications can occur.