linux-kernel - Re: kfree(0)

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Message-ID: <84144f020708180110i1558dc77p84241615c8ceb6a3@mail.gmail.com>
Date:	Sat, 18 Aug 2007 11:10:29 +0300
From:	"Pekka Enberg" <penberg@...helsinki.fi>
To:	"Thomas Gleixner" <tglx@...utronix.de>
Cc:	"Christoph Lameter" <clameter@....com>,
	"Satyam Sharma" <satyam@...radead.org>,
	"Andrew Morton" <akpm@...ux-foundation.org>,
	"Arjan van de Ven" <arjan@...radead.org>,
	"Tim Bird" <tim.bird@...sony.com>,
	"linux kernel" <linux-kernel@...r.kernel.org>
Subject: Re: kfree(0) - ok?

On 8/18/07, Thomas Gleixner <tglx@...utronix.de> wrote:
> If yes, who invented this 1980s reminiscence, where you got valid
> pointers for malloc(0) ?

Well, kmalloc(0) has always been legal and traditionally returned a
pointer to a smallest non-zero sized object. We did try to make
kmalloc(0) illegal for a while but ended up fixing up a bunch of
call-sites for little or no gain. I did propose that kmalloc(0) should
return NULL but Linus and others pointed out that we can do better and
not mix up out-of-memory and zero-sized allocations.
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