On Mon, 2017-08-07 at 11:27 +0100, Daniel P. Berrange wrote: > On Mon, Aug 07, 2017 at 11:21:25AM +0200, Knut Omang wrote: > > 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. > > > > > > > > When a subsequent listen() call is made with the same socket > > > > only one will succeed. > > > > > > > > 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. > > > > > > > > This test exposes two subtests: > > > > > > > > /socket/listen-serial > > > > /socket/listen-compete > > > > > > > > The "compete" subtest creates a number of threads and have them all > > > > trying 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. > > > > > > > > The serial version passes, probably in most versions of QEMU. > > > > > > > > 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. > > > > > > > > The problem seems to be present in all versions of QEMU. > > > > > > > > The original failure scenario occurred with VNC port allocation > > > > in a traditional Xen based build, in different code > > > > but with similar functionality. > > > > > > > > Reported-by: Bhavesh Davda <bhavesh.da...@oracle.com> > > > > Signed-off-by: Knut Omang <knut.om...@oracle.com> > > > > Reviewed-by: Yuval Shaia <yuval.sh...@oracle.com> > > > > Reviewed-by: Bhavesh Davda <bhavesh.da...@oracle.com> > > > > Reviewed-by: Girish Moodalbail <girish.moodalb...@oracle.com> > > > > --- > > > > tests/Makefile.include | 2 +- > > > > tests/test-listen.c | 253 > > > > ++++++++++++++++++++++++++++++++++++++++++- > > > > 2 files changed, 255 insertions(+) > > > > create mode 100644 tests/test-listen.c > > > > > > > > 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 += tests/test-bufferiszero$(EXESUF) > > > > gcov-files-check-bufferiszero-y = util/bufferiszero.c > > > > check-unit-y += tests/test-uuid$(EXESUF) > > > > check-unit-y += tests/ptimer-test$(EXESUF) > > > > +#check-unit-y += tests/test-listen$(EXESUF) > > > > gcov-files-ptimer-test-y = hw/core/ptimer.c > > > > check-unit-y += tests/test-qapi-util$(EXESUF) > > > > gcov-files-test-qapi-util-y = qapi/qapi-util.c > > > > @@ -769,6 +770,7 @@ tests/test-arm-mptimer$(EXESUF): > > > > tests/test-arm-mptimer.o > > > > tests/test-qapi-util$(EXESUF): tests/test-qapi-util.o > > > > $(test-util-obj-y) > > > > tests/numa-test$(EXESUF): tests/numa-test.o > > > > tests/vmgenid-test$(EXESUF): tests/vmgenid-test.o tests/boot-sector.o > > > > tests/acpi-utils.o > > > > +tests/test-listen$(EXESUF): tests/test-listen.o $(test-util-obj-y) > > > > > > > > tests/migration/stress$(EXESUF): tests/migration/stress.o > > > > $(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 > > > > reserved. > > > > + * Author: Knut Omang <knut.om...@oracle.com> > > > > + * > > > > + * This program is free software; you can redistribute it and/or modify > > > > + * it under the terms of the GNU General Public License version 2 > > > > + * as published by the Free Software Foundation. > > > > > > Can you change that to "version 2 or later" - per the LICENSE file, we > > > don't > > > accept contributions under "version 2 only" except for 4 specific subdirs: > > > > > > > > > "As of July 2013, contributions under version 2 of the GNU General > > > Public > > > License (and no later version) are only accepted for the following > > > files > > > or directories: bsd-user/, linux-user/, hw/vfio/, hw/xen/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 > > it as part of the merge? > > Since its a copyright statement, I'd prefer if you just sent a v7. I've no > other comments, so will queue it for merge once you resend, and send a pull > request once 2.11 opens up.
Ok, will do, Thanks, Knut > Regards, > Daniel
