Re: [ACPI] S3 and sigwait (was Re: 2.6.13-rc3: swsusp works (TP 600X))

[Pavel Machek <pavel@ucw.cz>]

Hi!

> > If you think it is a linux bug, can you produce small test case doing 
> > just the sigwait, and post it on l-k with big title "sigwait() breaks 
> > when straced, and on suspend"?
> > 
> > That way it is going to get some attetion, and you'll get either 
> > documentation or kernel fixed. 
> Looks like a linux bug to me. The refrigerator fake signal waked the
> task up and without restart for the sigwait case. How about below
> patch:

Is there chance to fix strace case, too? sigwait() is broken in more
than one way it seems...
								Pavel


>  linux-2.6.13-rc4-root/kernel/signal.c |   11 ++++++++++-
>  1 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff -puN kernel/signal.c~sigwait-suspend-resume kernel/signal.c
> --- linux-2.6.13-rc4/kernel/signal.c~sigwait-suspend-resume	2005-08-01 14:00:39.089460688 +0800
> +++ linux-2.6.13-rc4-root/kernel/signal.c	2005-08-01 14:30:13.821660384 +0800
> @@ -2188,6 +2188,7 @@ sys_rt_sigtimedwait(const sigset_t __use
>  	struct timespec ts;
>  	siginfo_t info;
>  	long timeout = 0;
> +	int recover = 0;
>  
>  	/* XXX: Don't preclude handling different sized sigset_t's.  */
>  	if (sigsetsize != sizeof(sigset_t))
> @@ -2225,15 +2226,23 @@ sys_rt_sigtimedwait(const sigset_t __use
>  			 * be awakened when they arrive.  */
>  			current->real_blocked = current->blocked;
>  			sigandsets(&current->blocked, &current->blocked, &these);
> +do_recover:
>  			recalc_sigpending();
>  			spin_unlock_irq(&current->sighand->siglock);
>  
>  			current->state = TASK_INTERRUPTIBLE;
>  			timeout = schedule_timeout(timeout);
>  
> -			try_to_freeze();
> +			if (try_to_freeze())
> +				recover = 1;

Can't you just goto do_recover here?

>  			spin_lock_irq(&current->sighand->siglock);
>  			sig = dequeue_signal(current, &these, &info);
> +			if (!sig && recover) {
> +				if (timeout == 0)
> +					timeout = MAX_SCHEDULE_TIMEOUT;
> +				recover = 0;
> +				goto do_recover;
> +			}
>  			current->blocked = current->real_blocked;
>  			siginitset(&current->real_blocked, 0);
>  			recalc_sigpending();
> _
> 

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