Re: [PATCH 1/4] sched/wakeup: Strengthen current_save_and_set_rtlock_wait_state()

[Sebastian Andrzej Siewior]

On 2021-09-09 12:59:16 [+0200], Peter Zijlstra wrote:
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -253,22 +254,24 @@ struct task_group;
>   */
>  #define current_save_and_set_rtlock_wait_state()			\
>  	do {								\
> -		lockdep_assert_irqs_disabled();				\
> -		raw_spin_lock(&current->pi_lock);			\
> +		unsigned long flags; /* may shadow */			\
could we haz __flags so no shadow?

> +									\
> +		raw_spin_lock_irqsave(&current->pi_lock, flags);	\
>  		current->saved_state = current->__state;		\
>  		debug_rtlock_wait_set_state();				\
> -		WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT);		\
> -		raw_spin_unlock(&current->pi_lock);			\
> +		smp_store_mb(current->__state, TASK_RTLOCK_WAIT);	\
> +		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	\

Sebastian