[zeromq-dev] Open file leak during DNS resolution while network is down (regression in libzmq-4.1.0 and libzmq-master) #1302

[Pieter Hintjens]

OK, thanks for the simple test case.

I'm not familiar enough with the internals of libzmq to debug this. I
see that tcp_connecter.cpp is closing the socket if it can't resolve
the hostname. However it's possible some error handling isn't right
here.


On Tue, Jan 20, 2015 at 5:04 AM, Tomas Krajca <tomas at repositpower.com> wrote:
> Hi Peter,
>
> It's actually really simple, I have posted example C code to github at
> https://github.com/zeromq/libzmq/issues/1302. Am I doing something wrong
> or is it that obvious?
>
> There is no need for a poller or anything like that. It seems that DNS
> resolution during zmq_connect() somehow does not release the file handle
> if network is down.
>
> Cheers,
> Tomas
>
>> Message: 19
>> Date: Mon, 19 Jan 2015 10:32:47 +0100
>> From: Pieter Hintjens <ph at imatix.com>
>> Subject: Re: [zeromq-dev] Open file leak during DNS resolution while
>>       network is down (regression in libzmq-4.1.0 and libzmq-master) #1302
>> To: ZeroMQ development list <zeromq-dev at lists.zeromq.org>
>> Cc: Mark Burgess <mark at repositpower.com>
>> Message-ID:
>>       <CADL5_shw3B+0YN4MYVCROEwufeH6_ThvxDKcw5c=vkfo4Dw5ew at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Can your C++ programmer make a minimal test case in C that reproduces
>> the problem?
>>
>> On Mon, Jan 19, 2015 at 1:55 AM, Tomas Krajca <tomas at repositpower.com> wrote:
>>> Hi,
>>>
>>> I've reported this weird bug https://github.com/zeromq/libzmq/issues/1302
>>> that we hit last week, I wonder if anybody experienced the same thing or can
>>> reproduce it. Basically, we saw a progressive file handle leak that crashed
>>> our application after about an hour of network outage.
>>>
>>> Any thoughts of which part of the code could the bug be in? We've got a C++
>>> programmer in our team but don't know enough about libzmq internals to try
>>> to fix this.
>>>
>>> Thanks,
>>> Tomas
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