Subject: Re: [PATCH 1/2] schedule: fix TASK_WAKEKILL vs SIGKILL race
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Oleg Nesterov <oleg@tv-sign.ru>, Andrew Morton <akpm@linux-foundation.org>,
       Ingo Molnar <mingo@elte.hu>,
       Dmitry Adamushko <dmitry.adamushko@gmail.com>,
       Roland McGrath <roland@redhat.com>, linux-kernel@vger.kernel.org
In-Reply-To: <20080604173318.GH3549@parisc-linux.org>
References: <20080604170905.GA10273@tv-sign.ru>
	 <20080604173318.GH3549@parisc-linux.org>
Content-Type: text/plain
Date: Wed, 04 Jun 2008 20:51:08 +0200
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On Wed, 2008-06-04 at 11:33 -0600, Matthew Wilcox wrote:
> On Wed, Jun 04, 2008 at 09:09:05PM +0400, Oleg Nesterov wrote:

> > --- 26-rc2/kernel/sched.c~1_SCHED_KILLABLE	2008-05-18 15:44:18.000000000 +0400
> > +++ 26-rc2/kernel/sched.c	2008-06-04 17:42:59.000000000 +0400
> > @@ -4510,12 +4510,10 @@ need_resched_nonpreemptible:
> >  	clear_tsk_need_resched(prev);
> >  
> >  	if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
> > -		if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
> > -				signal_pending(prev))) {
> > +		if (unlikely(signal_pending_state(prev->state, prev)))
> >  			prev->state = TASK_RUNNING;
> > -		} else {
> > +		else
> >  			deactivate_task(rq, prev, 1);
> > -		}
> 
> Getting rid of the extra braces is against CodingStyle:

No it doesn't.

>   Do not unnecessarily use braces where a single statement will do.
> 
>   if (condition)
>           action();
> 
>   This does not apply if one branch of a conditional statement is a single
>   statement. Use braces in both branches.
> 
>   if (condition) {
>           do_this();
>           do_that();
>   } else {
>           otherwise();
>   }

Which does not say anything about

 if (cond)
   stmt1;
 else
   stmt2;

like the above.

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