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List:       linux-mips
Subject:    Re: [PATCH] MIPS: Add len and addr validation for MAP_FIXED
From:       Ralf Baechle <ralf () linux-mips ! org>
Date:       2007-10-29 17:51:27
Message-ID: 20071029175127.GC3953 () linux-mips ! org
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On Sat, Oct 27, 2007 at 11:10:20PM -0700, David Daney wrote:

> mmap with MAP_FIXED was not validating the addr and len parameters.
> This leads to the failure of GCC's gcc.c-torture/execute/loop-2[fg].c
> testcases when using the o32 ABI on a 64 bit kernel.
> 
> These testcases try to mmap 65536 bytes at 0x7fff8000 and then access
> all the memory.  In 2.6.18 and 2.6.23.1 (and likely other versions as
> well) the kernel maps the requested memory, but since half of it is
> above 0x80000000 a SIGBUS is generated when it is accessed.
> 
> This patch moves the len validation above the MAP_FIXED processing so
> that it is always validated.  It also adds validation to the addr
> parameter for MAP_FIXED mappings.

Thanks, applied.

  Ralf

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