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From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: mingo@kernel.org, tglx@linutronix.de,
	linux-kernel@vger.kernel.org, will.deacon@arm.com,
	mpe@ellerman.id.au, bigeasy@linutronix.de, gkohli@codeaurora.org,
	neeraju@codeaurora.org
Subject: Re: [PATCH 2/2] sched: Introduce set_special_state()
Date: Mon, 30 Apr 2018 21:40:24 +0200	[thread overview]
Message-ID: <20180430194024.GA12217@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180430164545.GA10951@redhat.com>

On Mon, Apr 30, 2018 at 06:45:46PM +0200, Oleg Nesterov wrote:
> On 04/30, Peter Zijlstra wrote:
> >
> > --- a/kernel/signal.c
> > +++ b/kernel/signal.c
> > @@ -1968,7 +1968,7 @@ static void ptrace_stop(int exit_code, i
> >  	 * atomic with respect to siglock and should be done after the arch
> >  	 * hook as siglock is released and regrabbed across it.
> >  	 */
> > -	set_current_state(TASK_TRACED);
> > +	set_special_state(TASK_TRACED);
> 
> Yes, but please note the comment above, we need a barrier after state = TASK_TRACED,
> that is why ptrace_stop() does set_current_state(), not __set_current_state().

OK, so I got properly lost in that stuff.

The comment says it we need to set TASK_TRACED before clearing
JOBCTL_TRAPPING because of do_wait(), but I cannot seem to locate code
in do_wait() and below that cares about JOBCTL_TRAPPING.

Could you elucidate my tired brain?

  reply	other threads:[~2018-04-30 19:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-30 14:17 [PATCH 0/2] sched,kthread: Fix TASK_PARKED and special sleep states Peter Zijlstra
2018-04-30 14:17 ` [PATCH 1/2] kthread: Fix kthread_parkme() wait-loop Peter Zijlstra
2018-04-30 14:17 ` [PATCH 2/2] sched: Introduce set_special_state() Peter Zijlstra
2018-04-30 16:45   ` Oleg Nesterov
2018-04-30 19:40     ` Peter Zijlstra [this message]
2018-05-01  9:50       ` Peter Zijlstra
2018-05-01 13:59         ` Oleg Nesterov
2018-05-01 14:22           ` Peter Zijlstra
2018-05-01 15:10             ` Oleg Nesterov

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