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From: Peter Zijlstra <peterz@infradead.org>
To: Juri Lelli <juri.lelli@arm.com>
Cc: mingo@kernel.org, tglx@linutronix.de, rostedt@goodmis.org,
	xlpang@redhat.com, linux-kernel@vger.kernel.org,
	mathieu.desnoyers@efficios.com, jdesfossez@efficios.com,
	bristot@redhat.com
Subject: Re: [RFC][PATCH 6/8] sched/rtmutex: Refactor rt_mutex_setprio()
Date: Tue, 14 Jun 2016 16:08:27 +0200	[thread overview]
Message-ID: <20160614140827.GB3704@worktop> (raw)
In-Reply-To: <20160614131424.GK5981@e106622-lin>

On Tue, Jun 14, 2016 at 02:14:24PM +0100, Juri Lelli wrote:
> Hi,
> 
> still digesting this change, but I'll point out below why I think you
> are hitting a NULL ptr dereference (discussed on IRC).
> 
> On 07/06/16 21:56, Peter Zijlstra wrote:
> 
> > --- a/kernel/locking/rtmutex.c
> > +++ b/kernel/locking/rtmutex.c
> > @@ -256,61 +256,16 @@ rt_mutex_dequeue_pi(struct task_struct *
> >  	RB_CLEAR_NODE(&waiter->pi_tree_entry);
> >  }
> >  
> > +static void rt_mutex_adjust_prio(struct task_struct *p)
> >  {
> > +	struct task_struct *pi_task = NULL;
> >  
> > +	lockdep_assert_held(&p->pi_lock);
> >  
> > +	if (!task_has_pi_waiters(p))
> 
> Shouldn't this be the other way around?
> 
>  if (task_has_pi_waiters(p))
>  	pi_task = ...

Yeah, that would make more sense :-)

  reply	other threads:[~2016-06-14 14:08 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07 19:56 [RFC][PATCH 0/8] PI and assorted failings Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 1/8] rtmutex: Deboost before waking up the top waiter Peter Zijlstra
2016-06-14  9:09   ` Juri Lelli
2016-06-14 12:54     ` Peter Zijlstra
2016-06-14 13:20       ` Juri Lelli
2016-06-14 13:59         ` Peter Zijlstra
2016-06-14 16:36     ` Davidlohr Bueso
2016-06-14 17:01       ` Juri Lelli
2016-06-14 18:22   ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 2/8] sched/rtmutex/deadline: Fix a PI crash for deadline tasks Peter Zijlstra
2016-06-14 10:21   ` Juri Lelli
2016-06-14 12:30     ` Peter Zijlstra
2016-06-14 12:53     ` Xunlei Pang
2016-06-14 13:07       ` Juri Lelli
2016-06-14 16:39         ` Juri Lelli
2016-06-14 18:42   ` Steven Rostedt
2016-06-14 20:28     ` Peter Zijlstra
2016-06-15 16:14       ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 3/8] sched/deadline/rtmutex: Dont miss the dl_runtime/dl_period update Peter Zijlstra
2016-06-14 10:43   ` Juri Lelli
2016-06-14 12:09     ` Peter Zijlstra
2016-06-15 16:30   ` Steven Rostedt
2016-06-15 17:55     ` Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 4/8] rtmutex: Remove rt_mutex_fastunlock() Peter Zijlstra
2016-06-15 16:43   ` Steven Rostedt
2016-06-07 19:56 ` [RFC][PATCH 5/8] rtmutex: Clean up Peter Zijlstra
2016-06-14 12:08   ` Juri Lelli
2016-06-14 12:32     ` Peter Zijlstra
2016-06-14 12:41       ` Juri Lelli
2016-06-07 19:56 ` [RFC][PATCH 6/8] sched/rtmutex: Refactor rt_mutex_setprio() Peter Zijlstra
2016-06-14 13:14   ` Juri Lelli
2016-06-14 14:08     ` Peter Zijlstra [this message]
2016-06-07 19:56 ` [RFC][PATCH 7/8] sched,tracing: Update trace_sched_pi_setprio() Peter Zijlstra
2016-06-07 19:56 ` [RFC][PATCH 8/8] rtmutex: Fix PI chain order integrity Peter Zijlstra
2016-06-14 17:39   ` Juri Lelli
2016-06-14 19:44     ` Peter Zijlstra
2016-06-15  7:25       ` Juri Lelli
2016-06-27 12:23         ` Peter Zijlstra
2016-06-27 12:40           ` Thomas Gleixner
2016-06-28  9:05           ` Juri Lelli

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