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From: "H. Peter Anvin" <hpa@zytor.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com,
	Ian.Campbell@citrix.com, x86@kernel.org
Subject: Re: [PATCH] extend_brk and fixes to users of extend_brk (v1).
Date: Tue, 31 Jul 2012 08:49:21 -0700	[thread overview]
Message-ID: <5017FE81.3080903@zytor.com> (raw)
In-Reply-To: <1343731376-20658-1-git-send-email-konrad.wilk@oracle.com>

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.

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.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  parent reply	other threads:[~2012-07-31 15:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-31 10:42 [PATCH] extend_brk and fixes to users of extend_brk (v1) Konrad Rzeszutek Wilk
2012-07-31 10:42 ` [PATCH 1/3] xen/mmu/p2m: Check extend_brk for NULL Konrad Rzeszutek Wilk
2012-07-31 13:48   ` Konrad Rzeszutek Wilk
2012-07-31 10:42 ` [PATCH 2/3] xen/p2m: Reserve 4MB of _brk space for P2M leafs when populating back Konrad Rzeszutek Wilk
2012-07-31 10:42 ` [PATCH 3/3] x86: Let extend_brk return a NULL pointer instead of just BUG_ON Konrad Rzeszutek Wilk
2012-07-31 15:49 ` H. Peter Anvin [this message]
2012-07-31 16:15   ` [PATCH] extend_brk and fixes to users of extend_brk (v1) Konrad Rzeszutek Wilk
2012-07-31 16:41     ` [Xen-devel] " Jan Beulich
2012-07-31 17:29       ` Konrad Rzeszutek Wilk

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