Re: hang when using pthread and fork in 1.5.23-1 and snapshot 20070118, and now 1.5.24-1.

[Peter Rehley <peter at rehley dot net>]

Hello,

I tried the latest release of cygwin1.dll (1.5.24-1) and it still is  
hanging in the same way.  I've tried to debug further with gdb, but  
so far I haven't got any useful information out of gdb.

I'll keep trying to get some debug information, but if any one else  
can reproduce the problem I would be most appreciative.

Thanks,
Peter

p.s. my machines spec's are
windows xp, sp2, 2.93 GHz, 760MB ram.
windows xp, sp1 2.39 GHz, 508MB ram.
both are single processor units.

On Jan 19, 2007, at 6:03 PM, Peter Rehley wrote:

> Hello,
>
> One of the applications I've been working with has hanging issues.   
> It will sometimes work properly, and sometimes it will hang and  
> never continue through the rest of the program.
>
> I've created a simple test case that does some of what the  
> application does, and it will hang too. The test case has a loop  
> that continually creates a pthread.  The pthread calls a function  
> that forks and execve's to another program.  Eventually the main  
> program will be unable to fork, and it will hang inside of the  
> pthread after the thread's function has completed.   However, I can  
> also get two other different results depending on how the program  
> is compiled and run.
>
> 1) pthread_create failed : rc 11 - valid error.
>   build with "g++ -DPRFAIL main.cc"
>   and run without redirecting output.  Adds additional printf  
> statements to output
> 2) fork called but never returns.  one hang situation.
>    build with g++ main.cc
>    and run with redirecting output to a file.
> 3) Unable to create fork, but program doesn't appear to leave  
> thread and program hangs.
>    build with g++ main.cc
>    and run without redirecting output.
>
> I suspect, maybe incorrectly, that the hangs are race conditions.   
> I'm hoping that someone will be able to take the test case and be  
> able to reproduce what I'm seeing.
>
> The machine is a fresh install of windows xp only.  No webcam  
> drivers or other known programs that interact badly with cygwin.  I  
> have AVG antivirus installed but even with it uninstalled the  
> program can still hang.
>
> I've attached the cygcheck output and the simple test case.
>
> Thanks,
> Peter
>
> <main.cc>
> <cygcheck.out>
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