libthr patch

[Tim Robbins]

On Thu, Feb 19, 2004 at 09:28:50AM +0300, Mike Makonnen wrote:

> Index: sys/kern/kern_thr.c
[...]
> +int
> +thr_wake(struct thread *td, struct thr_wake_args *uap)
> +	/* thr_id_t id */
> +{
> +	PROC_LOCK(((struct thread *)uap->id)->td_proc);
> +	((struct thread *)uap->id)->td_lthrflags |= LTF_THRWAKEUP;
> +	PROC_UNLOCK(((struct thread *)uap->id)->td_proc);
> +	wakeup_one((void *)uap->id);
> +	return (0);
> +}
[...]

Make sure you fix thr_wake() to check that uap->id is valid before you
commit this patch. Something like this would be safer but slower:

	struct thread *td1;

	PROC_LOCK(td->td_proc);
	FOREACH_THREAD_IN_PROC(td->td_proc, td1)
		if (td1 == (struct thread *)uap->id)
			break;
	if (td1 == NULL) {
		PROC_UNLOCK(td->td_proc);
		return (ESRCH);
	}
	td1->td_lthrflags |= LTF_THRWAKEUP;
	wakeup_one(td1);
	PROC_UNLOCK(td->td_proc);
	return (0);

(I'm not sure that it's safe to call wakeup_one() on a thread pointer
that isn't curthread without holding the proc lock, so I changed that too.)


Tim