Subject: Re: [PATCH] Check for online cpus before bringing them up
From: Shaohua Li <shaohua.li@intel.com>
To: Andrew Morton <akpm@osdl.org>
Cc: vatsa@in.ibm.com, torvalds@osdl.org, linux-kernel@vger.kernel.org,
       bryce@osdl.org
In-Reply-To: <20060316170814.02fa55a1.akpm@osdl.org>
References: <20060316174447.GA8184@in.ibm.com>
	 <20060316170814.02fa55a1.akpm@osdl.org>
Content-Type: text/plain
Date: Fri, 17 Mar 2006 09:16:54 +0800
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On Thu, 2006-03-16 at 17:08 -0800, Andrew Morton wrote:
> Srivatsa Vaddagiri <vatsa@in.ibm.com> wrote:
> >
> > Bryce reported a bug wherein offlining CPU0 (on x86 box) and then subsequently
> > onlining it resulted in a lockup. 
> > 
> > On x86, CPU0 is never offlined. The subsequent attempt to online CPU0
> > doesn't take that into account. It actually tries to bootup the already
> > booted CPU. Following patch fixes the problem (as acknowledged by
> > Bryce). Please consider for inclusion in 2.6.16.
> > 
> > 
> 
> Is x86 the only architecture which is exposed to this?
I guess i386 is the only architecture exposing to this. i386 uses a
slight different method to do cpu hotadd (prepare cpu, and then up cpu).
This is to workaround some issues like tsc synchronizing.

Thanks,
Shaohua

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