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Message-ID: <001701c0c557$02a861b0$0200a8c0@lifelesswks>
From: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
To: <cygwin AT cygwin DOT com>
References: <037701c0c3ab$9049bf30$0200a8c0 AT lifelesswks> <20010413221222 DOT C5606 AT dothill DOT com> <006001c0c4af$179b79c0$0200a8c0 AT lifelesswks> <20010414223139 DOT A906 AT redhat DOT com>
Subject: Re: fork expert needed: (was Re: pthreads update for the adventurous)
Date: Sun, 15 Apr 2001 12:51:44 +1000
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----- Original Message -----
From: "Christopher Faylor" <cgf AT redhat DOT com>
To: <cygwin AT cygwin DOT com>
Sent: Sunday, April 15, 2001 12:31 PM
Subject: Re: fork expert needed: (was Re: pthreads update for the
adventurous)


> On Sat, Apr 14, 2001 at 04:49:43PM +1000, Robert Collins wrote:
> >----- Original Message -----
> >From: "Jason Tishler" <Jason DOT Tishler AT dothill DOT com>
> >To: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
> >Cc: <cygwin AT cygwin DOT com>
> >Sent: Saturday, April 14, 2001 12:12 PM
> >Subject: Re: pthreads update for the adventurous
> >
> >> > 3. The Python regression tests consistently crash during
test_popen2
> >> > with the following error message:
> >> >
> >>>H:\src\Python-2.1b2a-threads\python.exe: *** couldn't release
memory
> >>>0x1A02C000(5013504) for
>
>>>'H:\src\Python-2.1b2a-threads\build\lib.cygwin_nt-4.0-1.3.0-i686-2.1\
imageop.dll'
> >>>alignment, Win32 error 487
>
> This error means that Cygwin was trying to relocate a DLL load point
in
> a child process to the same location as it existed in the parent and
was
> unsuccesful in doing so.  The 487 error means "Invalid address".  That
> may that that the memory is already occupied.
>
> There's not much that can be done to rectify this, unfortunately.
> Possibly if someone really wants to debug this situation there might
be
> something that will be obvious but it is pretty painful to debug,
> unfortunately.
>
> I added this dll relocation stuff last year to help with perl.  It
> wasn't fun.
>
> cgf
>

Oh. Well I infer that it only occurs with threads enabled in python, or
Jason wouldn't be telling us. Any hints Chris for possible races/locks
that might prevent the child doing the relocation if the parent has
active threads ? (We could look at just suspending all the other
threads, but that is definately non-posix behaviour (timers would be
missed etc).

I'm off to dream up some directions for Jason et al to tweak the code as
test cases..

Rob


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