[zeromq-dev] Signaler.cpp hangs on windows intermittently

[Pieter Hintjens]

In CZMQ we simulate ephemeral ports by looking for free ports within a
certain range. If we define a range for Windows use, and document
this, applications can stay away from that and it might be easier to
configure firewalls to accept that range.

-Pieter

On Thu, May 9, 2013 at 11:06 AM, Michał Sznajder
<michalsznajder at gmail.com> wrote:
> On Thu, May 9, 2013 at 4:08 PM, KIU Shueng Chuan <nixchuan at gmail.com> wrote:
>> Browsing through the code history, ephemeral ports were originally used
>> before switching over to fixed port 5905.
>>
>> Does anyone know the reason for the change to fixed port?
>
> I might have been related to
> http://lists.zeromq.org/pipermail/zeromq-dev/2011-September/013450.html
>
>>
>> We might want to find out why before making any changes.
>>
>> On 9 May, 2013 9:55 PM, "Pieter Hintjens" <ph at imatix.com> wrote:
>>>
>>> Martin,
>>>
>>> I think evreryone liked the idea of ephemeral ports, but it needs
>>> someone who can reproduce the problem to make the change and pull
>>> request. Any volunteers?
>>>
>>> -Pieter
>>>
>>> On Thu, May 9, 2013 at 4:52 AM, Martin Robinson
>>> <martin.robinson at dai.co.uk> wrote:
>>> > Pieter,
>>> >
>>> > If making changes to this area of signaller.cpp, you might also review
>>> > the change I suggested back on 22nd March to make this use ephemeral ports
>>> > instead of a fixed port number.  Seems to solve the problem completely of
>>> > the connect failing on XP in signaler_t::make_fdpair.
>>> >
>>> > Martin
>>> >
>>> > -----Original Message-----
>>> > From: zeromq-dev-bounces at lists.zeromq.org
>>> > [mailto:zeromq-dev-bounces at lists.zeromq.org] On Behalf Of Pieter Hintjens
>>> > Sent: 06 May 2013 20:55
>>> > To: ZeroMQ development list
>>> > Subject: Re: [zeromq-dev] Signaler.cpp hangs on windows intermittently
>>> >
>>> > Has this been fixed on master but not backported to 3.x?
>>> >
>>> > Usually it's up to individual contributors to either do the backport (a
>>> > git cherrypick) or ask someone to help do it.
>>> >
>>> > I'm happy to backport the fix for the next 3.2.4 release if someone
>>> > tells me what commit it was.
>>> >
>>> > -Pieter
>>> >
>>> > On Mon, May 6, 2013 at 8:32 PM, Felipe Farinon
>>> > <felipe.farinon at powersyslab.com> wrote:
>>> >> Why wasn't this patch released yet?
>>> >>
>>> >> In my application i'm trying to fix it by using Mutex considering the
>>> >> case that waiting (WaitForSingleObject) on the mutex results in
>>> >> WAIT_ABANDONED. It seems that it has been fixed. Should I submit a
>>> >> patch?
>>> >>
>>> >> Em 19/03/2013 16:45, Pau escreveu:
>>> >>> Hi,
>>> >>>
>>> >>> I had this problem some weeks ago. This was my problem:
>>> >>>
>>> >>> I do not know all possible reasons to generate a fatal wsa_assert(..)
>>> >>> but there is at least one:
>>> >>>
>>> >>> I have seen that in XP it is possible that line 301  rc = connect
>>> >>> (*w_, (sockaddr *) &addr, sizeof (addr)); returns an error when a
>>> >>> socket tries to connect to 5905 and this has happened many times.
>>> >>> Windows uses port numbers starting near 1400 and XP has a limit at
>>> >>> 5000.
>>> >>> In W7 this does not look as a problem because maximum is 65000 It
>>> >>> sounds as if the number was big enough but apart from the fact that
>>> >>> ZMQ uses a big number of connections (at least in my tests) I have
>>> >>> experienced that Windows jumps port numbers by 7, so 5000 happens
>>> >>> sometimes with catastrophic consequences.
>>> >>>
>>> >>> Perhaps there are other reasons (actually this problem does not
>>> >>> happen like that in W7) anyway whatever crashes between
>>> >>>
>>> >>> HANDLE sync = CreateEvent (NULL, FALSE, TRUE, TEXT
>>> >>> ("zmq-signaler-port-sync")); and SetEvent (sync);
>>> >>>
>>> >>> will leave the event signaled and any other application in the system
>>> >>> will hang. Closing all apps in a system fixes it.
>>> >>>
>>> >>> KIU Shueng Chuan submitted a patch that sets the event when crash
>>> >>> avoiding other applications to ge hanged:
>>> >>>
>>> >>> https://github.com/zeromq/libzmq/pull/514
>>> >>>
>>> >>> That worked for me...
>>> >>>
>>> >>> If you search for "zmq-signaler-port-sync" in previous mails in this
>>> >>> list you will see the complete thread.
>>> >>>
>>> >>> best,
>>> >>>
>>> >>> Pau
>>> >>>
>>> >>> El 19/03/2013 17:18, Felipe Farinon escribió:
>>> >>>> Hi,
>>> >>>>
>>> >>>> The code
>>> >>>> HANDLE sync = CreateEvent (&sa, FALSE, TRUE, TEXT
>>> >>>> ("Global\\zmq-signaler-port-sync"));
>>> >>>>
>>> >>>> in signaler.cpp:262 hangs intermittently when starting zeromq
>>> >>>> context through zmq_init in my application. I'm not able to
>>> >>>> reproduce this bug with a minimal test case. I'm running my
>>> >>>> application in a Windows 7 with zeromq compiled with VS2010.
>
> Michał
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