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Date: Tue, 7 Aug 2012 14:59:56 +0400
Message-ID: <CACgPhYrM3C9V673hfhbJ7BVzNBgLzeUustAVfpaLapij5VuB1A@mail.gmail.com>
Subject: Re: Race condition that leads to random crashes in cygwin-based builds.
From: Andrey Khalyavin <halyavin AT google DOT com>
To: cygwin AT cygwin DOT com
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On Aug 7 Corinna Vinschen wrote:
>On Aug  6 19:31, Andrey Khalyavin wrote:
>> 2012/8/6 Corinna Vinschen wrote:
>> > Andrey?
>> >
>> > On Jul 24 15:57, Corinna Vinschen wrote:
>> >> On Jul 24 17:25, Andrey Khalyavin wrote:
>> >> > Hi, we have build bots that crash randomly on Windows XP and rarely on
>> >> > Windows 7.
>> >> > [...]
>> >> > 5. Task switching happens and first process proceeds to execute
>> >> > GetVersionEx with
>> >> > version cleared by memset and so not having its size set.
>> >> > 6. GetVersionEx returns error and first process fails to start.
>> >> >
>> >> > If there is no easy way to add synchronization to wincapc::init, I
>> >> > suggest to make
>> >> > wincap a regular (not shared) variable.
>> >>
>> >> There's another way, afaics.  The idea here was that wincap is only
>> >> ever set once, and even *if* the information is written twice, the
>> >> content will be identical.
>> >>
>> >> So, afaics, the above problem is a result of using memset at all.  At
>> >> startup, wincap is all 0 anyway, so the memset is not required and
>> >> apparently it even hurts.  Weird that nobody saw this problem before.
>> >>
>> >> I applied a patch which should fix this problem.  Please give the
>> >> next developer snapshot from http://cygwin.com/snapshots/ a try,
>> >> or build yourself from CVS.
>> >
>> > Ping?  Any feedback?  Did you ever try a snapshot?
>>
>> I updated our cygwin with core libraries from 20120725 snapshot. There
>> are still crashes in our build, I'm investigating them. Haven't got a
>> crash dump yet. This time I have to catch them on the bots instead of
>> local computer.
>
>Please use the *latest* snapshot from CVS, 20120803.  There were other
>potential reasons for crashes which only have been (tried to) fix in
>the latest snapshot.

Thank you. I will update cygwin before I do a new step in investigating our
build issues (need to implement some way to get crash dumps on bots).

Andrey Khalyavin.

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