Re: [PATCH] extend_brk and fixes to users of extend_brk (v1).

From: Konrad Rzeszutek Wilk
Date: Tue Jul 31 2012 - 12:24:17 EST


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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