RE: [patch][rfc] acpi: do not use kmem caches

Skywing
2009-01-05T05:44:07Z

-----Original Message-----
From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Nick Piggin
Sent: Sunday, January 04, 2009 11:15 PM
To: Len Brown
Cc: Christoph Hellwig; Alexey Starikovskiy; Pekka Enberg; Linux Memory Management List; linux-acpi@vger.kernel.org
Subject: Re: [patch][rfc] acpi: do not use kmem caches

> > I think they are here to stay. We are running
> > an interpreter in kernel-space with arbitrary input,
> > so I think the ability to easily isolate run-time memory leaks
> > on a non-debug system is important.
> I don't really see the connection. Or why being an interpreter is so
> special. Filesystems, network stack, etc run in kernel with arbitrary
> input. If kmem caches are part of a security strategy, then it's
> broken... You'd surely have to detect bad input before the interpreter
> turns it into a memory leak (or recover afterward, in which case it
> isn't a leak).

I think that the purposes of these was to act as a debugging aid, for example, if there were BIOS-supplied AML that was triggering a leak. The point being here that a network card driver has a much more well-defined set of what can happen than a fully pluggable interpreter for third party code.

[Of course, this is just my interpretation from following the discussion; I'm not otherwise involved.]

- S