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Re: [Qemu-devel] [PATCH 2/2] socket: Handle race condition between binds
From: |
Knut Omang |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] socket: Handle race condition between binds to the same port |
Date: |
Wed, 14 Jun 2017 13:34:11 +0200 |
On Wed, 2017-06-14 at 09:17 +0100, Daniel P. Berrange wrote:
> On Fri, Jun 09, 2017 at 09:19:49PM +0200, Knut Omang wrote:
> > If an offset of ports is specified to the inet_listen_saddr function(),
> > and two or more processes tries to bind from these ports at the same time,
> > occasionally more than one process may be able to bind to the same
> > port. The condition is detected by listen() but too late to avoid a failure.
> >
> > This function is called by socket_listen() and used
> > by all socket listening code in QEMU, so all cases where any form of dynamic
> > port selection is used should be subject to this issue.
> >
> > Add code to close and re-establish the socket when this
> > condition is observed, hiding the race condition from the user.
> >
> > This has been developed and tested by means of the
> > test-listen unit test in the previous commit.
> > Enable the test for make check now that it passes.
> >
> > Signed-off-by: Knut Omang <address@hidden>
> > Reviewed-by: Bhavesh Davda <address@hidden>
> > Reviewed-by: Yuval Shaia <address@hidden>
> > Reviewed-by: Girish Moodalbail <address@hidden>
> > ---
> > tests/Makefile.include | 2 +-
> > util/qemu-sockets.c | 106 +++++++++++++++++++++++++++++-------------
> > 2 files changed, 76 insertions(+), 32 deletions(-)
>
> FYI, the changes here will conflict with a pull request that I have
> pending, so please rebase against this PR
>
> https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg01940.html
Ok, v3 will be from this base,
Knut
>
> Regards,
> Daniel
- [Qemu-devel] [PATCH 0/2] Unit test+fix for problem with QEMU handling of multiple bind()s to the same port, Knut Omang, 2017/06/09
- [Qemu-devel] [PATCH 2/2] socket: Handle race condition between binds to the same port, Knut Omang, 2017/06/09
- [Qemu-devel] [PATCH 1/2] Add test-listen - a stress test for QEMU socket listen, Knut Omang, 2017/06/09
- Re: [Qemu-devel] [PATCH 0/2] Unit test+fix for problem with QEMU handling of multiple bind()s to the same port, no-reply, 2017/06/09
- Re: [Qemu-devel] [PATCH 0/2] Unit test+fix for problem with QEMU handling of multiple bind()s to the same port, Eric Blake, 2017/06/09
- Re: [Qemu-devel] [PATCH 0/2] Unit test+fix for problem with QEMU handling of multiple bind()s to the same port, no-reply, 2017/06/09
- Re: [Qemu-devel] [PATCH 0/2] Unit test+fix for problem with QEMU handling of multiple bind()s to the same port, no-reply, 2017/06/09