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removing MAP_FIXED

To: GNU libc hacker <libc-hacker at sourceware dot cygnus dot com>
Subject: removing MAP_FIXED
From: Ulrich Drepper <drepper at redhat dot com>
Date: 31 Dec 2000 00:31:53 -0800
Reply-To: drepper at cygnus dot com (Ulrich Drepper)

I just added some code which should in theory enable us to remove
MAP_FIXED from the mmap calls in libpthread.  The background is that
Linux honors the address, if possible, even if MAP_FIXED is not given.
Using MAP_FIXED is wrong because it simply unmaps whatever memory
region is currently mapped in the given address which is fatal.


But it does not work (yet).  ex6 crashes if I remove MAP_FIXED (you
have to compile for a target without thread register, like i386 and
not i686).  I don't know the reason yet, will try to investigate it
further tomorrow.  In case somebody has the time to look at it while I
get some zzzs I'd love to hear about the findings.  Oh, I'm using
2.4.0-test12.

-- 
---------------.                          ,-.   1325 Chesapeake Terrace
Ulrich Drepper  \    ,-------------------'   \  Sunnyvale, CA 94089 USA
Red Hat          `--' drepper at redhat.com   `------------------------

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