Subject: Re: Don't use UFS_DIRHASH
To: David Malone <>
From: Daniel Carosone <>
List: tech-kern
Date: 08/25/2006 16:51:26
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On Wed, Aug 23, 2006 at 07:34:14AM +0100, David Malone wrote:
> > I presume this surrounds each allocation with extra padding filled
> > with known content, and checks that the padding is undisturbed later?
> > That more general solution sounds very useful too; I'm not sure if we
> > have something like this, but we probably should.
> It actually puts each allocation in its own page. When the allocation
> is freed the vm system sets up the page to cause a fault if the
> page is accessed. That way we can catch code that uses-after-free.

Ah. Coverity has helped in this area, but even so both ideas sound
like they could be of value. Any volunteers? :)

> It's very wasteful of memory, but is only intended as a debugging tool.

I bet :)

> (At the moment you attach the option to a particular allocation type.)

I imagine we'd set it as a per-pool flag, pretty much the same thing.

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