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Re: User/Group Problem

To: "Maciej W. Rozycki" <>
Subject: Re: User/Group Problem
From: Ralf Baechle <>
Date: Wed, 15 Nov 2000 08:52:45 +0100
Cc: Ian Chilton <>,,, Andreas Jaeger <>
In-reply-to: <>; from on Tue, Nov 14, 2000 at 03:19:11PM +0100
References: <> <>
On Tue, Nov 14, 2000 at 03:19:11PM +0100, Maciej W. Rozycki wrote:

> > There is second interpretation of this problem - the address passed to
> > mmap is bogus, so this computation needs to be fixed.
>  Where is it written mmap() is allowed to fail when a bogus VM address is
> passed but MAP_FIXED is not set?  I believe mmap() should choose a
> different VM address in this case, as long as much enough contiguous VM
> space is available anywhere to satisfy the requested length.

No argument about that, I do agree.

>  Surely, map_segment() (see dl-load.c) might call mmap(0, ...) after
> mmap(<some_address>, ...) fails when MAP_FIXED is not set but wouldn't
> that be a dirty hack?  We'd better fix the kernel. isn't linked to the same base address as all other libraries for
obscure reasons.  Right now dl-machine.h use the constant value of 0x5ffe0000
as the base address which it assumes all libraries to be linked to - and that
makes us calculate the wrong base address which we're passing to mmap.

So we've got two bugs, not just one.  I knew about the part since
Linux/MIPS has shared libs.  It's just that this is the first time this bug
bites us.


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