Date: Fri, 27 Aug 2010 23:54:02 +0200 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r211896 - head/sbin/hastd Message-ID: <20100827215402.GB2077@garage.freebsd.pl> In-Reply-To: <20100827213827.GD2396@deviant.kiev.zoral.com.ua> References: <201008272049.o7RKn63o007138@svn.freebsd.org> <20100827213827.GD2396@deviant.kiev.zoral.com.ua>
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--TakKZr9L6Hm6aLOc Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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? --=20 Pawel Jakub Dawidek http://www.wheelsystems.com pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --TakKZr9L6Hm6aLOc Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAkx4M/oACgkQForvXbEpPzSemQCePvHcTbrskj5kyX4ZspOgCWoh /iYAnAsnL57koDHXhA3063IMp9YU5jcJ =2+VM -----END PGP SIGNATURE----- --TakKZr9L6Hm6aLOc--
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