From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [ANNOUNCE] 3.12.5-rt6
Date: Tue, 17 Dec 2013 15:35:45 +0100
Message-ID: <52B06141.5020803@linutronix.de>
References: <20131216091431.GA13796@linutronix.de>  <1387264591.5340.23.camel@marge.simpson.net>  <20131217063156.6ac3bfed@gandalf.local.home>  <20131217124248.GA21694@linutronix.de>  <20131217091624.65be757c@gandalf.local.home> <1387290376.2399.11.camel@marge.simpson.net>
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Cc: Steven Rostedt <rostedt@goodmis.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	John Kacur <jkacur@redhat.com>
To: Mike Galbraith <bitbucket@online.de>
Return-path: <linux-kernel-owner@vger.kernel.org>
In-Reply-To: <1387290376.2399.11.camel@marge.simpson.net>
Sender: linux-kernel-owner@vger.kernel.org
List-Id: linux-rt-users.vger.kernel.org

On 12/17/2013 03:26 PM, Mike Galbraith wrote:
> On Tue, 2013-12-17 at 09:16 -0500, Steven Rostedt wrote: 
>>
>>> @@ -1129,11 +1127,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
>>>  		 * is actually now running somewhere else!
>>>  		 */
>>>  		while (task_running(rq, p)) {
>>> -			if (match_state) {
>>> -				if (!unlikely(check_task_state(p, match_state)))
>>> -					return 0;
>>> +			if (match_state && !check_task_state(p, match_state))
>>
>> Ah, it was that "!unlikely(" that caused me to miss the '!'. That
>> should have been: likely(!check_task_state()). But anyway, I rather
>> just keep what you wrote and drop the unlikely altogether.
> 
> Maybe better would be to put the thing back inline, with a brief
> reference to the race.

There is similar code in
- task_is_stopped_or_traced()
- task_is_traced()

and I didn't get around to have one function for this stupid check
since the check is always a little different.

> -Mike

Sebastian