Re: [PATCH 2/4] printk: disable optimistic spin during panic

[John Ogness]

> Is there something that prevents panic CPU from NMI hlt CPU which is
> in console_trylock() under raw_spin_lock_irqsave()?
>
>  CPU0				CPU1
> 				console_trylock_spinnning()
> 				 console_trylock()
> 				  down_trylock()
> 				   raw_spin_lock_irqsave(&sem->lock)
>
>  panic()
>   crash_smp_send_stop()
>    NMI 			-> 		HALT

This is a good point. I wonder if console_flush_on_panic() should
perform a sema_init() before it does console_trylock().

John