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Date: Thu, 4 Aug 2005 15:10:30 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Postmaster core dumps
Message-ID: <20050804131030.GR14783@calimero.vinschen.de>
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References: <0MKu60-1E0L272OZO-0000t4 AT mxeu10 DOT kundenserver DOT de> <20050803153956 DOT GH14783 AT calimero DOT vinschen DOT de>
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On Aug  3 17:39, Corinna Vinschen wrote:
> On Aug  3 17:17, Novaelec wrote:
> > Hello Corinna,
> > 
> > I think the problem is in cygserver because the bug is related to semaphores
> > when I use gdb. [...]
> 
> Sorry to say that, but to me it looks like a bug in postmaster.  Looking
> into the stacktrace printed when the SEGV occurs, I'm getting this:
> 
> $ addr2line -e /bin/cygwin1.dll 610D6127 610028FE 610173A9 61017A6E 61017D1F 6109E76C 610942FF
> /home/corinna/src/cygwin/vanilla/newlib/libc/machine/i386/memset.S:45
> /home/corinna/src/cygwin/vanilla/winsup/cygwin/cygheap.cc:331
> /home/corinna/src/cygwin/vanilla/winsup/cygwin/dtable.cc:375
> /home/corinna/src/cygwin/vanilla/winsup/cygwin/dtable.cc:486
> /home/corinna/src/cygwin/vanilla/winsup/cygwin/dtable.cc:532
> /home/corinna/src/cygwin/vanilla/winsup/cygwin/syscalls.cc:127
> 
> This is the stacktrace of a dup() call on the tty slave descriptor.  It
> looks like a heap corruption to me.  It has certainly nothing to do with
> semaphores.

FYI, I tracked the problem down to a point that I can savely say,
it's neither a bug in postgresql, nor in cygserver.  It has nothing
to do with semaphores.  As noted above, it's a heap problem, but
it's entirely inside Cygwin.  Unfortunately I have no fix so far.
For the curious, it's reproducible with

	int fd;
	for (;;)
	  fd = dup (0);


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Project Co-Leader          mailto:cygwin AT cygwin DOT com
Red Hat, Inc.

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