From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: "H. Peter Anvin" <hpa@zytor.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 12:15:15 -0400 [thread overview]
Message-ID: <20120731161515.GQ4789@phenom.dumpdata.com> (raw)
In-Reply-To: <5017FE81.3080903@zytor.com>
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!
next prev parent reply other threads:[~2012-07-31 16:24 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 ` [PATCH] extend_brk and fixes to users of extend_brk (v1) H. Peter Anvin
2012-07-31 16:15 ` Konrad Rzeszutek Wilk [this message]
2012-07-31 16:41 ` [Xen-devel] " Jan Beulich
2012-07-31 17:29 ` Konrad Rzeszutek Wilk
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