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Date: Fri, 4 Sep 2015 11:38:56 +0200
From: Petr Mladek <pmladek@suse.com>
Subject: Re: [RFC PATCH 10/14] ring_buffer: Fix more races when terminating
 the producer in the benchmark
Message-ID: <20150904093856.GI22739@pathway.suse.cz>
References: <1438094371-8326-1-git-send-email-pmladek@suse.com>
 <1438094371-8326-11-git-send-email-pmladek@suse.com>
 <20150803143323.426ea2fc@gandalf.local.home>
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To: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>, Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, Josh Triplett <josh@joshtriplett.org>, Thomas Gleixner <tglx@linutronix.de>, Linus Torvalds <torvalds@linux-foundation.org>, Jiri Kosina <jkosina@suse.cz>, Borislav Petkov <bp@suse.de>, Michal Hocko <mhocko@suse.cz>, linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>, live-patching@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org

On Mon 2015-08-03 14:33:23, Steven Rostedt wrote:
> On Tue, 28 Jul 2015 16:39:27 +0200
> Petr Mladek <pmladek@suse.com> wrote:
> 
> > @@ -384,7 +389,7 @@ static int ring_buffer_consumer_thread(void *arg)
> >  
> >  static int ring_buffer_producer_thread(void *arg)
> >  {
> > -	while (!kthread_should_stop() && !kill_test) {
> > +	while (!break_test()) {
> >  		ring_buffer_reset(buffer);
> >  
> >  		if (consumer) {
> > @@ -393,11 +398,15 @@ static int ring_buffer_producer_thread(void *arg)
> >  		}
> >  
> >  		ring_buffer_producer();
> > -		if (kill_test)
> > +		if (break_test())
> >  			goto out_kill;
> >  
> >  		trace_printk("Sleeping for 10 secs\n");
> >  		set_current_state(TASK_INTERRUPTIBLE);
> > +		if (break_test()) {
> > +			__set_current_state(TASK_RUNNING);
> 
> Move the setting of the current state to after the out_kill label.

Please, find below the updated version of this patch.

I also reverted some changes in the consumer code. It never stays
in a loop for too long and it must stay in ring_buffer_producer()
until "reader_finish" variable is set.