From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Frediano Ziglio <frediano.ziglio@citrix.com>
Cc: Ian Jackson <Ian.Jackson@citrix.com>,
Stefano Stabellini <Stefano.Stabellini@citrix.com>,
Ian Campbell <Ian.Campbell@citrix.com>,
Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH v2 qemu-traditional] qemu: Fix race condition when opening ports
Date: Mon, 9 Dec 2013 15:50:02 +0000 [thread overview]
Message-ID: <52A5E6AA.3030606@citrix.com> (raw)
In-Reply-To: <4BE945389935F64490EB1C02F3502F63135E5C@AMSPEX01CL01.citrite.net>
On 09/12/13 15:23, Frediano Ziglio wrote:
>> -----Original Message-----
>> From: xen-devel-bounces@lists.xen.org [mailto:xen-devel-
>> bounces@lists.xen.org] On Behalf Of Andrew Cooper
>> Sent: 09 December 2013 1:27 PM
>> To: Xen-devel
>> Cc: Andrew Cooper; Ian Jackson; Ian Campbell; Stefano Stabellini
>> Subject: [Xen-devel] [PATCH v2 qemu-traditional] qemu: Fix race condition
>> when opening ports
>>
>> Two Qemus can race to bind the same VNC port. It is valid for multiple
>> bind()s on the same socket to succeed, but only the first listen() will
>> succeed.
>>
>> In the case that two Qemus are starting at the same time, and both trying to
>> grab the next free VNC port, the second one will fail with an EADDRINUSE,
>> and bail with a fatal error which renders the domain functionally useless.
>>
>> In the case that listen() fails with EADDRINUSE, rebind the socket again and
>> try for the next port.
>>
>> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
>> CC: Ian Campbell <Ian.Campbell@citrix.com>
>> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
>> CC: Stefano Stabellini <stefano.stabellini@citrix.com>
>> Release-acked-by: George Dunlap <george.dunlap@eu.citrix.com>
> Andrew, if you are upstream other people stuff you should at least give credit to the original author.
>
> Frediano
>
The original author was "xenhg" according to the history. It is not even
clear from the original bug ticket who the author could have been.
In this case, my Signed-off-by line falls into category b) of the
Developer’s Certificate of Origin.
This is an unfortunate problem with attempting to weed through a
neglected patch queue where proper authorship was not considered at the
time of commit.
~Andrew
next prev parent reply other threads:[~2013-12-09 15:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-09 13:10 [PATCH qemu-traditional] qemu: Fix race condition when binding ports Andrew Cooper
2013-12-09 13:17 ` George Dunlap
2013-12-09 13:25 ` Andrew Cooper
2013-12-09 13:27 ` [PATCH v2 qemu-traditional] qemu: Fix race condition when opening ports Andrew Cooper
2013-12-09 13:36 ` Ian Campbell
2013-12-09 15:23 ` Frediano Ziglio
2013-12-09 15:50 ` Andrew Cooper [this message]
2013-12-10 15:28 ` Ian Jackson
2013-12-10 15:38 ` Frediano Ziglio
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