Subject: Re: Zero-length mmaps
To: Kailash Sethuraman <>
From: Thor Lancelot Simon <>
List: tech-kern
Date: 08/21/2006 12:11:19
On Mon, Aug 21, 2006 at 03:01:29PM +0000, Kailash Sethuraman wrote:
> On 8/20/06, Jason Thorpe <> wrote:
> >
> >NetBSD's mmap should be fixed.  We should probably version the symbol
> >so old programs continue to run, but new programs get the new behavior.
> >
> >From my code reading, please correct me if I am wrong,
> It does seem to be the case that when a mmap with length 0 is
> specified,size passed to uvm_mmap() can be 0.
> Does this warrant a PR for ld.elf_so, and possibly other programs in
> base that do 0 length mmaps?
> Or must valgrind be  taught to accomodate this case in netbsd?

I will note that we do not claim anywhere to slavishly conform to SUS (of
any version); rather, we say we will conform to _reasonable_ standards.

The interface in question (mmap(2)) is a BSD interface, to which SUS seems
to have made a largely arbitrary change.  Whether we change it to match SUS
or not, valgrind should probably be fixed to understand the traditional

  Thor Lancelot Simon	                           

  "We cannot usually in social life pursue a single value or a single moral
   aim, untroubled by the need to compromise with others."      - H.L.A. Hart