From: Mark Kettenis <mark.kettenis@xs4all.nl>
Subject: Re: rpki-client: pthreads first unlock then signal
To: Job Snijders <job@openbsd.org>
Cc: tech@openbsd.org
Date: Tue, 24 Jun 2025 00:25:06 +0200

> Date: Mon, 23 Jun 2025 22:13:51 +0000
> From: Job Snijders <job@openbsd.org>
> 
> While this is not fixing a bug, intuition and literature suggest that
> unlocking mutexes before signaling might help prevent the
> freshly-woken-up thread from humping against the lock.

Where did you find this questionable advice?

> This also provides consistency with how things are approached in
> parser.c:proc_parser() around line 1268.
> 
> OK?
> 
> Index: parser.c
> ===================================================================
> RCS file: /cvs/src/usr.sbin/rpki-client/parser.c,v
> diff -u -p -r1.158 parser.c
> --- parser.c	23 Jun 2025 22:01:14 -0000	1.158
> +++ parser.c	23 Jun 2025 22:09:27 -0000
> @@ -1106,10 +1106,10 @@ parse_worker(void *arg)
>  			if (pthread_mutex_lock(&globalmsgq_mtx) != 0)
>  				errx(1, "pthread_mutex_lock");
>  			ibufq_concat(globalmsgq, myq);
> -			if (pthread_cond_signal(&globalmsgq_cond) != 0)
> -				errx(1, "pthread_cond_signal");
>  			if (pthread_mutex_unlock(&globalmsgq_mtx) != 0)
>  				errx(1, "pthread_mutex_unlock");
> +			if (pthread_cond_signal(&globalmsgq_cond) != 0)
> +				errx(1, "pthread_cond_signal");
>  		}
>  	}
>  
> 
>