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From: Dmitry Vyukov <dvyukov@google.com>
To: Andy Lutomirski <luto@kernel.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>
Subject: Re: Making KASAN compatible with VMAP_STACK
Date: Mon, 23 Jul 2018 09:40:36 +0200	[thread overview]
Message-ID: <CACT4Y+aP4QSGBiLWt0iNHVJ4nMc_phthK9P+gTMd4d=exaAKwA@mail.gmail.com> (raw)
In-Reply-To: <CALCETrW4F33LWWA=cWYZ2N9=veCmVfjhCCLnSv2qh=32fOAf-w@mail.gmail.com>

On Sun, Jul 22, 2018 at 7:52 PM, Andy Lutomirski <luto@kernel.org> wrote:
> Hi all-
>
> It would be really nice to make KASAN compatible with VMAP_STACK.
> Both are valuable memory debugging features, and the fact that you
> can't use both is disappointing.
>
> As far as I know, there are only two problems:
>
> 1. The KASAN shadow population code is a mess, and adding *anything*
> to the KASAN shadow requires magical, fragile incantations.  It should
> be cleaned up so that ranges can be easily populated without needing
> to very carefully align things, call helpers in the right order, etc.
> The core KASAN code should figure it out by itself.
>
> 2. The vmalloc area is potentially extremely large.  It might be
> necessary to have a way to *depopulate* shadow space when stacks get
> freed or, more generally, when vmap areas are freed.  Ideally KASAN
> would integrate with the core vmalloc/vmap code and it would Just Work
> (tm).  And, as a bonus, we'd get proper KASAN protection of vmalloced
> memory.
>
> Any volunteers to fix this?

Hi Andy,

I understand that having most configs as orthogonal settings that can
be enabled independently is generally good in intself, but I would
like to understand what does VMAP_STACK add on top of KASAN in terms
of debugging capabilities?

  reply	other threads:[~2018-07-23  7:41 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-22 17:52 Making KASAN compatible with VMAP_STACK Andy Lutomirski
2018-07-23  7:40 ` Dmitry Vyukov [this message]
2018-07-23 11:18   ` Mark Rutland
2018-07-23 11:55     ` Dmitry Vyukov
2018-07-23 12:42       ` Mark Rutland
2018-07-23 12:51         ` Dmitry Vyukov
2018-12-17 15:10           ` Dmitry Vyukov

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