Re: [PATCH] esp: Make driver SMP-correct

[Jan Dittmer]

James Nelson wrote:
>  static inline int serial_paranoia_check(struct esp_struct *info,
>  					char *name, const char *routine)
>  {
> @@ -209,34 +197,38 @@
>  	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
>  	unsigned long flags;
>  
> -	if (serial_paranoia_check(info, tty->name, "rs_stop"))
> -		return;
> +	spin_lock_irqsave(&info->irq_lock, flags);
> +
> +	if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
> +		goto out;

>  static void rs_start(struct tty_struct *tty)
>  {
>  	struct esp_struct *info = (struct esp_struct *)tty->driver_data;
>  	unsigned long flags;
> -	
> -	if (serial_paranoia_check(info, tty->name, "rs_start"))
> -		return;
> -	
> -	save_flags(flags); cli();
> +
> +	spin_lock_irqsave(&info->irq_lock, flags);
> +
> +	if (unlikely(serial_paranoia_check(info, tty->name, __FUNCTION__)))
> +		goto out;
> +

This will deadlock. serial_paranoia_check also unconditionally tries to
take the lock.

Jan
-
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