svn commit: r211896 - head/sbin/hastd

[Kostik Belousov]

On Fri, Aug 27, 2010 at 11:54:02PM +0200, Pawel Jakub Dawidek wrote:
> On Sat, Aug 28, 2010 at 12:38:27AM +0300, Kostik Belousov wrote:
> > > --- head/sbin/hastd/primary.c	Fri Aug 27 20:48:12 2010	(r211895)
> > > +++ head/sbin/hastd/primary.c	Fri Aug 27 20:49:06 2010	(r211896)
> > > @@ -1988,7 +1988,9 @@ guard_thread(void *arg)
> > >  				rw_unlock(&hio_remote_lock[ii]);
> > >  			}
> > >  		}
> > > -		(void)cv_timedwait(&hio_guard_cond, &hio_guard_lock, timeout);
> > > +		/* Sleep only if a signal wasn't delivered in the meantime. */
> > > +		if (!sigexit_received && !sighup_received && !sigchld_received)
> > > +			cv_timedwait(&hio_guard_cond, &hio_guard_lock, timeout);
> > >  		mtx_unlock(&hio_guard_lock);
> > >  	}
> > >  	/* NOTREACHED */
> > I wanted to say that this is racy, because if a signal is delivered after
> > the check is done but before the sleep, you loose.
> 
> Yes, I know it is racy, but the race isn't critical anymore, as we will
> eventually wait at most 10 seconds to handle signals.
> 
> > After looking at the signal handler, I noted that you call not async-safe
> > functions in the handler. This is easy way to get undefined behaviour,
> > i.e. probably crash. And wakeup from the handler would have the same
> > race as sigXXX_received check.
> 
> Which aren't async-safe? pthread stuff?

Yes. All pthread_* namespace is not async-signal safe.
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