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Message-ID: <3EB76D55.7040503@coppice.org>
Date: Tue, 06 May 2003 16:07:49 +0800
From: Steve Underwood <steveu AT coppice DOT org>
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To: cygwin AT cygwin DOT com
Subject: A problem with mmap on Win98
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Hi all,

I am using the current version of cygwin (1.3.22). When I build gcc to 
cross-compile for the TI MSP430 MCUs the result works OK on 2000 and XP 
machines. On some Win98 and Me machines it works, but on others it 
crashes with a segmentation violation. I traced this to a problem with 
anonymous mmap. If I keep calling mmap on the problem machines it keeps 
returning the same memory pointer twice. If I patch GCC to check for a 
repeat of the same memory pointer, and allocate again until it gets a 
different pointer, my GCC build seems to run OK on these problem machines.

The results are not random. They follow a pattern. If I allocate 65536 
byte blocks, I consistently get the same pointer twice, before I get a 
pointer 65536 bytes greater. If I allocate 16384 byte blocks, I get four 
pointers incrementing by 0x4000 each. Then I get a repeat of the fourth 
pointer. Then I get four more properly incrementing pointers.

I tried downloading the source code for cygwin, to build it, and do a 
little debugging of my own. However, the make files build most of the 
code, and then fail saying there is no rule to make 
/usr/lib/w32api/Makefile needed by /lib/. The make dependancies are a 
little intertwined, and I gave up trying to find the cause of this problem.

Can anyone help?

Regards,
Steve



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