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Date: Sun, 10 Aug 2008 16:51:57 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       linux-kernel@vger.kernel.org, Yinghai Lu <yinghai.lu@amd.com>,
       Andi Kleen <ak@suse.de>, Glauber Costa <gcosta@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] [PATCH] x86:  Restore proper vector locking during cpu
 hotplug
References: <m11w0xu9hd.fsf@frodo.ebiederm.org>
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Eric W. Biederman wrote:
> Having cpu_online_map change during assign_irq_vector can result
> in some really nasty and weird things happening.  The one that
> bit me last time was accessing non existent per cpu memory for non
> existent cpus.
> 
> This locking was removed in a sloppy x86_64 and x86_32 merge patch.
> 
> Guys can we please try and avoid subtly breaking x86 when we are
> merging files together?

Queuing for tip:x86/urgent.