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Date: Sat, 13 Dec 2003 17:05:36 +0100
From: Ralf Baechle <ralf@linux-mips.org>
To: Peter Horton <pdh@colonel-panic.org>
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org
Subject: Re: Possible shared mapping bug in 2.4.23 (at least MIPS/Sparc)
Message-ID: <20031213160536.GA13271@linux-mips.org>
References: <20031213114134.GA9896@skeleton-jack>
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On Sat, Dec 13, 2003 at 11:41:34AM +0000, Peter Horton wrote:

> The current MIPS 2.4 kernel (from CVS) currently allows fixed shared
> mappings to violate D-cache aliasing constraints.
> 
> The check for illegal fixed mappings is done in
> arch_get_unmapped_area(), but these mappings are granted in
> get_unmapped_area() and arch_get_unmapped_area() is never called.
> 
> A quick look at sparc and sparc64 seem to show the same problem.

Ehh...  <asm/pgtable.h> defines HAVE_ARCH_UNMAPPED_AREA therefore
get_unmapped_area calls the arch's version of arch_get_unmapped_area
instead of the generic version in mm/mmap.c

  Ralf