linux-kernel - Re: [RFC 0/4] CONFIG_STABLE to switch off development checks

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Date:	Sat, 02 Jun 2007 09:28:38 -0700
From:	Jeremy Fitzhardinge <jeremy@...p.org>
To:	Dave Kleikamp <shaggy@...ux.vnet.ibm.com>
CC:	Christoph Lameter <clameter@....com>, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, akpm@...ux-foundation.org
Subject: Re: [RFC 0/4] CONFIG_STABLE to switch off development checks

Dave Kleikamp wrote:
> I'm on Christoph's side here.  I don't think it makes sense for any code
> to ask to allocate zero bytes of memory and expect valid memory to be
> returned.
>   

Yes, everyone agrees on that.  If you do kmalloc(0), its never OK to
dereference the result.  The question is whether kmalloc(0) should complain.

> Would a compromise be to return a pointer to some known invalid region?
> This way the kmalloc(0) call would appear successful to the caller, but
> any access to the memory would result in an exception.
>   

Yes, that's what Christoph has posted.  I'm slightly concerned about
kmalloc() returning the same non-NULL address multiple times, but it
seems sound otherwise.

    J
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