Date: Fri, 20 Feb 2004 00:47:33 +1100 From: Tim Robbins <tjr@freebsd.org> To: Mike Makonnen <mtm@identd.net> Cc: freebsd-threads@freebsd.org Subject: Re: libthr patch Message-ID: <20040219134733.GA38023@cat.robbins.dropbear.id.au> In-Reply-To: <20040219062850.GC1074@mobile.acs-et.com> References: <20040219062850.GC1074@mobile.acs-et.com>
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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
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