Date: Fri, 17 Mar 2006 19:43:22 +0530
From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Andrew Morton <akpm@osdl.org>
Cc: torvalds@osdl.org, linux-kernel@vger.kernel.org, shaohua.li@intel.com,
       bryce@osdl.org, ashok.raj@intel.com
Subject: Re: [PATCH] Check for online cpus before bringing them up
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Reply-To: vatsa@in.ibm.com
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On Fri, Mar 17, 2006 at 01:04:12AM -0800, Andrew Morton wrote:
> OK..  I guess we should fix those architectures while we're thinking about it.

Only x86 has this bug, so only x86 needs to be fixed. Neverthless
Ashok's patch [1] should address all architectures that may implement
smp_prepare_cpu() in future as well.

> How well tested is this?  From my reading, this will cause
> enable_nonboot_cpus() to panic.  Is that intended?

I have done some basic test of the patch using Bryce's scripts.
Regarding enable_nonboot_cpus(), from my reading of it, it should not
call smp_prepare_cpu on online cpus, so the check added should not cause
it to panic. Am I missing something?

Finally, I think the patch Ashok posted sometime back [1] is probably a more
neater solution to this bug (he probably needs to modify it slightly to 
remove smp_prepare_cpu from enable_nonboot_cpus as well).


[1] http://lkml.org/lkml/2006/3/17/103

-- 
Regards,
vatsa
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