From owner-svn-src-all@FreeBSD.ORG Sat Aug 28 08:44:00 2010 Return-Path: Delivered-To: svn-src-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5185F1065670; Sat, 28 Aug 2010 08:44:00 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.zoral.com.ua (mx0.zoral.com.ua [91.193.166.200]) by mx1.freebsd.org (Postfix) with ESMTP id B87918FC12; Sat, 28 Aug 2010 08:43:59 +0000 (UTC) Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id o7S8htlY033909 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 28 Aug 2010 11:43:55 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4) with ESMTP id o7S8htBI053756; Sat, 28 Aug 2010 11:43:55 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.4/8.14.4/Submit) id o7S8htRI053755; Sat, 28 Aug 2010 11:43:55 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Sat, 28 Aug 2010 11:43:55 +0300 From: Kostik Belousov To: Pawel Jakub Dawidek Message-ID: <20100828084355.GH2396@deviant.kiev.zoral.com.ua> References: <201008272049.o7RKn63o007138@svn.freebsd.org> <20100827213827.GD2396@deviant.kiev.zoral.com.ua> <20100827215402.GB2077@garage.freebsd.pl> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="y3SX8pAkUMTjg65a" Content-Disposition: inline In-Reply-To: <20100827215402.GB2077@garage.freebsd.pl> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.2 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-2.5 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_20, DNS_FROM_OPENWHOIS autolearn=no version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org Subject: Re: svn commit: r211896 - head/sbin/hastd X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Aug 2010 08:44:00 -0000 --y3SX8pAkUMTjg65a Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 aft= er > > the check is done but before the sleep, you loose. >=20 > 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. >=20 > > After looking at the signal handler, I noted that you call not async-sa= fe > > 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. >=20 > Which aren't async-safe? pthread stuff? Yes. All pthread_* namespace is not async-signal safe. --y3SX8pAkUMTjg65a Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkx4zEsACgkQC3+MBN1Mb4jViACg3CXV6cQ8RlDfZP69PRseydkR lDUAn2dc13lxrLoKqBuCGGevRLokdKGC =3Pgt -----END PGP SIGNATURE----- --y3SX8pAkUMTjg65a--