Re: cpu stopper threads and setaffinity leads to deadlock

[Thomas Gleixner]

Prasad.

On Thu, 2 Aug 2018, Peter Zijlstra wrote:
> 
> So why didn't you do the 'obvious' parallel to what you did for
> cpu_stop_queue_two_works(), namely:

Is that patch fixing the issue for you?

> --- a/kernel/stop_machine.c
> +++ b/kernel/stop_machine.c
> @@ -81,6 +81,7 @@ static bool cpu_stop_queue_work(unsigned
>  	unsigned long flags;
>  	bool enabled;
>  
> +	preempt_disable();
>  	raw_spin_lock_irqsave(&stopper->lock, flags);
>  	enabled = stopper->enabled;
>  	if (enabled)
> @@ -90,6 +91,7 @@ static bool cpu_stop_queue_work(unsigned
>  	raw_spin_unlock_irqrestore(&stopper->lock, flags);
>  
>  	wake_up_q(&wakeq);
> +	preempt_enable();
>  
>  	return enabled;
>  }
>