linux-kernel - Re: [PATCH] extend_brk and fixes to users of extend

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Message-ID: <20120731161515.GQ4789@phenom.dumpdata.com>
Date:	Tue, 31 Jul 2012 12:15:15 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	linux-kernel@...r.kernel.org, xen-devel@...ts.xensource.com,
	Ian.Campbell@...rix.com, x86@...nel.org
Subject: Re: [PATCH] extend_brk and fixes to users of extend_brk (v1).

On Tue, Jul 31, 2012 at 08:49:21AM -0700, H. Peter Anvin wrote:
> On 07/31/2012 03:42 AM, Konrad Rzeszutek Wilk wrote:
> >
> >  [PATCH 3/3] x86: Let extend_brk return a NULL pointer instead of
> >
> >makes extend_brk not do BUG_ON and instead just return NULL. This allows
> >us to handle the bootup issues more gracefully.
> >
> 
> NAK.  The whole point of the brk allocator is that users specify the
> upper limit on what they may need and stick to it.  Hence it is a
> fatal code bug if that is ever exceeded.  We want to catch those
> errors, not "handle" them.

OK, thanks for pointing that out.
> 
> This means you're either abusing the brk allocator to do something
> it is not meant to do... which may mean you can a failure in *other*
> code, or you have a bug in your code that you haven't fixed.

Its the latter - and of one of the patches in this patchset fixes that.

Will drop the one that alter extend_brk.
Thanks!
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