Re: [PATCH v2] rtmutex: take the waiter lock with irqs off

[Frederic Weisbecker <fweisbec@gmail.com>]

On Mon, Nov 18, 2013 at 03:10:21PM +0100, Peter Zijlstra wrote:
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -746,13 +746,23 @@ void irq_exit(void)
>  #endif
>  
>  	account_irq_exit_time(current);
> -	trace_hardirq_exit();
>  	sub_preempt_count(HARDIRQ_OFFSET);
> -	if (!in_interrupt() && local_softirq_pending())
> +	if (!in_interrupt() && local_softirq_pending()) {
> +		/*
> +		 * Temp. disable hardirq context so as not to confuse lockdep;
> +		 * otherwise it might think we're running softirq handler from
> +		 * hardirq context.
> +		 *
> +		 * Should probably sort this someplace else..
> +		 */
> +		trace_hardirq_exit();
>  		invoke_softirq();
> +		trace_hardirq_enter();
> +	}
>  
>  	tick_irq_exit();
>  	rcu_irq_exit();
> +	trace_hardirq_exit();

Looks like a change we really want!

Thanks!

>  }
>  
>  void raise_softirq(unsigned int nr)