From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59867) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1deeED-0003WZ-9Z for qemu-devel@nongnu.org; Mon, 07 Aug 2017 05:21:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1deeEA-0001SV-4F for qemu-devel@nongnu.org; Mon, 07 Aug 2017 05:21:37 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:28975) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1deeE9-0001Rf-QM for qemu-devel@nongnu.org; Mon, 07 Aug 2017 05:21:34 -0400 Message-ID: <1502097685.3624.6.camel@oracle.com> From: Knut Omang Date: Mon, 07 Aug 2017 11:21:25 +0200 In-Reply-To: <20170807084524.GF18259@redhat.com> References: <7c4ddf95a57f7dfa546c11f8a08a9091b8bd1ceb.1501362828.git-series.knut.omang@oracle.com> <20170807084524.GF18259@redhat.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v6 1/4] tests: Add test-listen - a stress test for QEMU socket listen List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: Gerd Hoffmann , Paolo Bonzini , qemu-devel@nongnu.org On Mon, 2017-08-07 at 09:45 +0100, Daniel P. Berrange wrote: > On Sat, Jul 29, 2017 at 11:18:15PM +0200, Knut Omang wrote: > > There's a potential race condition between multiple bind()'s > > attempting to bind to the same port, which occasionally > > allows more than one bind to succeed against the same port. > >=20 > > When a subsequent listen() call is made with the same socket > > only one will succeed. > >=20 > > The current QEMU code does however not take this situation into account > > and the listen will cause the code to break out and fail even > > when there are actually available ports to use. > >=20 > > This test exposes two subtests: > >=20 > > /socket/listen-serial > > /socket/listen-compete > >=20 > > The "compete" subtest creates a number of threads and have them all try= ing to bind > > to the same port with a large enough offset input to > > allow all threads to get it's own port. > > The "serial" subtest just does the same, except in series in a > > single thread. > >=20 > > The serial version passes, probably in most versions of QEMU. > >=20 > > The parallel version exposes the problem in a relatively reliable way, > > eg. it fails a majority of times, but not with a 100% rate, occasional > > passes can be seen. Nevertheless this is quite good given that > > the bug was tricky to reproduce and has been left undetected for > > a while. > >=20 > > The problem seems to be present in all versions of QEMU. > >=20 > > The original failure scenario occurred with VNC port allocation > > in a traditional Xen based build, in different code > > but with similar functionality. > >=20 > > Reported-by: Bhavesh Davda > > Signed-off-by: Knut Omang > > Reviewed-by: Yuval Shaia > > Reviewed-by: Bhavesh Davda > > Reviewed-by: Girish Moodalbail > > --- > > =C2=A0tests/Makefile.include |=C2=A0=C2=A0=C2=A02 +- > > =C2=A0tests/test-listen.c=C2=A0=C2=A0=C2=A0=C2=A0| 253 ++++++++++++++++= ++++++++++++++++++++++++++- > > =C2=A02 files changed, 255 insertions(+) > > =C2=A0create mode 100644 tests/test-listen.c > >=20 > > diff --git a/tests/Makefile.include b/tests/Makefile.include > > index 7af278d..b37c0c8 100644 > > --- a/tests/Makefile.include > > +++ b/tests/Makefile.include > > @@ -128,6 +128,7 @@ check-unit-y +=3D tests/test-bufferiszero$(EXESUF) > > =C2=A0gcov-files-check-bufferiszero-y =3D util/bufferiszero.c > > =C2=A0check-unit-y +=3D tests/test-uuid$(EXESUF) > > =C2=A0check-unit-y +=3D tests/ptimer-test$(EXESUF) > > +#check-unit-y +=3D tests/test-listen$(EXESUF) > > =C2=A0gcov-files-ptimer-test-y =3D hw/core/ptimer.c > > =C2=A0check-unit-y +=3D tests/test-qapi-util$(EXESUF) > > =C2=A0gcov-files-test-qapi-util-y =3D qapi/qapi-util.c > > @@ -769,6 +770,7 @@ tests/test-arm-mptimer$(EXESUF): tests/test-arm-mpt= imer.o > > =C2=A0tests/test-qapi-util$(EXESUF): tests/test-qapi-util.o $(test-util= -obj-y) > > =C2=A0tests/numa-test$(EXESUF): tests/numa-test.o > > =C2=A0tests/vmgenid-test$(EXESUF): tests/vmgenid-test.o tests/boot-sect= or.o tests/acpi-utils.o > > +tests/test-listen$(EXESUF): tests/test-listen.o $(test-util-obj-y) > > =C2=A0 > > =C2=A0tests/migration/stress$(EXESUF): tests/migration/stress.o > > =C2=A0 $(call quiet-command, $(LINKPROG) -static -O3 $(PTHREAD_LIB) -o = $@ $< ,"LINK","$(TARGET_DIR)$@") > > diff --git a/tests/test-listen.c b/tests/test-listen.c > > new file mode 100644 > > index 0000000..5c07537 > > --- /dev/null > > +++ b/tests/test-listen.c > > @@ -0,0 +1,253 @@ > > +/* > > + * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserv= ed. > > + *=C2=A0=C2=A0=C2=A0=C2=A0Author: Knut Omang > > + * > > + * This program is free software; you can redistribute it and/or modif= y > > + * it under the terms of the GNU General Public License version 2 > > + * as published by the Free Software Foundation. >=20 > Can you change that to "version 2 or later" - per the LICENSE file, we do= n't > accept contributions under "version 2 only" except for 4 specific subdirs= : >=20 >=20 > =C2=A0 "As of July 2013, contributions under version 2 of the GNU General= Public > =C2=A0=C2=A0=C2=A0License (and no later version) are only accepted for th= e following files > =C2=A0=C2=A0=C2=A0or directories: bsd-user/, linux-user/, hw/vfio/, hw/xe= n/xen_pt*." Oh, sorry - I wasn't aware of this, +"...or later" is fine with me. Would you like me to send a v7 of the set with only that change, or can you= amend=C2=A0 it as part of the merge? Thanks, Knut >=20 > > + * > > + * Test parallel port listen configuration with > > + * dynamic port allocation > > + */ >=20 >=20 > Regards, > Daniel