Re: [PATCH] sched: fix tsk->pi_lock isn't held when do_set_cpus_allowed()

[Wanpeng Li]

On 8/25/15 4:30 PM, Ingo Molnar wrote:
> * Wanpeng Li <wanpeng.li@xxxxxxxxxxx> wrote:
>
> > > > --- a/kernel/cpuset.c
> > > > +++ b/kernel/cpuset.c
> > > > @@ -2376,8 +2376,12 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
> > > >   void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
> > > >   {
> > > > +	unsigned long flags;
> > > > +
> > > >   	rcu_read_lock();
> > > > +	raw_spin_lock_irqsave(&tsk->pi_lock, flags);
> > > >   	do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
> > > > +	raw_spin_lock_irqsave(&tsk->pi_lock, flags);
> > > Just curious, Will introduce deadlock after acquire lock twice? ;)
> > Could you point out where acquires lock twice?
> In the code you quote?

Shame me, sorry for sending out the wrong version. I fix in it soon in v2.

Regards,
Wanpeng Li

> Thanks,
>
> 	Ingo

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