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Date: Tue, 24 Feb 2009 11:06:16 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: [1.7] rebaseall doesn't solve the problem
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On Feb 20 21:27, Charles Wilson wrote:
> Using process explorer, I find that for SOME reason, even in the parent
> perl, the Cwd.dll (one of the DLLs shipped with perl, in
> /usr/lib/perl5/5.10/i686-pc-cygwin/auto/Cwd/Cwd.dll) is being loaded in
> a strange location:
> 
> Image Base: 0x5d6a0000
> Location in Parent: 0x00860000
> Location in Child : 0x014E0000
> 
> I can't see that there is any conflict at the image base location of
> 0x5d6a0000, so I'm not sure why, in the parent, Cwd.dll was loaded that
> low.  However, the low memory region is rife with conflict, and in fact,
> in the child:
> 
> C:\Windows\system32\locale.nls
> image base: 0x0
> mapped location: 0x00960000
> mapped size:     0x0037F000
> 
> which means that locale.nls extends all the way down to 0x005E1000, so
> Cwd.dll can't go at 0x00860000.

Hm?  Isn't that end_of_mapped_region = mapped_location + mapped_size?

> Rebasing won't solve this problem, because Cwd.dll is NOT being loaded
> at the rebased (0x5d6a0000) location even tho, as far as I can tell,
> there is no conflict there. Instead, it's being loaded at a traffic
> heavy location for no good reason that I can see -- and I keep getting
> hit by passing cars.
> 
> Help?

I'm wondering if that's a result of ASLR in Vista.  The document
http://taossa.com.nyud.net:8080/archive/bh08sotirovdowd.pdf describes,
starting at page 11, a registry key to influence Vista's ASLR behaviour.
Does that change the behaviour for you?

If so, there's nothing Cygwin can do against that.  In the long run,
only a native fork() implementation would help.


Corinna

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

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