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Date: Fri, 7 Jun 2013 16:22:19 -0700
From: Tejun Heo <tj@kernel.org>
To: "weiqi@kylinos.com.cn" <weiqi@kylinos.com.cn>
Cc: torvalds <torvalds@linux-foundation.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: race condition in schedule_on_each_cpu()
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On Fri, Jun 07, 2013 at 10:24:50AM +0800, weiqi@kylinos.com.cn wrote:
> >Before the commit you originally quoted, the calling thread could be
> preempted and migrated to another CPU before get_online_cpus() thus
> ending up executing the function twice on the new cpu but skipping the
> old one.
> 
> does this situation will happen in "Full preemption" config, on 3.0.30-rt50?

Sure, if the fix hasn't been backported.

Thanks.

-- 
tejun