Message-ID: <50F5D559.4090909@coverity.com>
Date: Tue, 15 Jan 2013 17:16:57 -0500
From: Tom Honermann <thonermann@coverity.com>
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To: <cygwin@cygwin.com>
Subject: Re: Intermittent failures with ctrl-c (was: retrieving process exit codes)
References: <20121222024943.GA5773@ednor.casa.cgf.cx> <20121222031430.GA8355@ednor.casa.cgf.cx> <50D57818.1070706@gmail.com> <20121222175041.GA14475@ednor.casa.cgf.cx> <20121223165621.GA9935@ednor.casa.cgf.cx> <50DCB454.9030400@coverity.com> <20121229215725.GA18847@ednor.casa.cgf.cx> <50E23F98.1060004@coverity.com> <20130101053606.GB18911@ednor.casa.cgf.cx> <50E48743.5040401@coverity.com> <20130102204821.GA6524@ednor.casa.cgf.cx> <50E4A597.1060600@coverity.com>
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On 01/02/2013 04:24 PM, Tom Honermann wrote:
> On 01/02/2013 03:48 PM, Christopher Faylor wrote:
>> I managed to duplicate a hang by really stressing ctrl-c a loop.  It
>> uncovers some rather amazing Windows behavior which I have to think
>> about.  Apparently ExitThread can be called recursively within the
>> thread that Windows creates to handle CTRL-C.
>
> I'm glad you could reproduce.  Based on your description, this sounds
> like a separate issue and not a regression introduced by the workarounds
> you put in place for the ExitProcess / ExitThread race.  Correct?
>
> I wonder if this is the same issue I'm experiencing though.  I'm only
> pressing ctrl-c once and it sounds like you might be deliving a ctrl-c
> to the same process multiple times.  That may not be relevant to the
> root cause however.

I noticed that some changes were checked in related to signal handling 
and process termination recently, so I downloaded the most recent 
snapshot (20130114) and tested again.  I was still able to produce 
hanging processes (including hangs of strace.exe) by hitting ctrl-c in a 
mintty window while Cygwin processes ran in an infinite loop inside of a 
.bat file.  I was able to produce a hang ~1 out of 20 times.

If you are still working on this, then I apologize for the noise. 
Otherwise, assuming you are still looking at this, if I can provide 
something further that would be helpful, please let me know.

Tom.


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