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Date: Mon, 8 Sep 2003 19:42:03 -0400
From: Christopher Faylor <cgf-rcm AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: similar crash in mmap for 1.5.3-1
Message-ID: <20030908234203.GA4227@redhat.com>
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References: <3F5D0343 DOT 60300 AT prime-analytics DOT com>
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On Mon, Sep 08, 2003 at 03:31:31PM -0700, John Joganic wrote:
>Previous posts described a bug in mmap called via malloc. I am seeing a 
>bug in mmap itself.  The following test does not map large amounts of 
>memory, nor does it leak.  It crashes however, after 4193 (0x1061) 
>iterations every time.  Like the malloc crash, the call stack references 
>strdup, and in this case calloc as well.  On a Linux box, this program 
>runs to completion without a hitch.

I guess I have to point this out every single time someone mentions
strdup.  mmap does not call strdup.  You can't get a reliable crash dump
from a stripped DLL, which cygwin1.dll is, of course.  I can't believe
that this has to be a FAQ entry but apparently it does.

If you want to help with a back trace, you have to build your own version
of the DLL with debugging symbols.

Is this clear everyone?  Do you get it, all of you future archive
spelunkers?  No more mentions of strdup and mmap.  No more backtraces
with of an unstripped cygwin DLL.  The only thing that shows us is that
the crash occurred in the DLL itself and we would get that from the *.stackdump
file.

As long as we're at it, you might want to check out http://cygwin.com/problems.html .
Simple test cases are a godsend but so is information from cygcheck.exe.

cgf

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