From: Andrey Konovalov <andreyknvl@google.com>
To: David Hildenbrand <david@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
George Kennedy <george.kennedy@oracle.com>,
Konrad Rzeszutek Wilk <konrad@darnok.org>,
Will Deacon <will.deacon@arm.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Christoph Hellwig <hch@infradead.org>,
kasan-dev <kasan-dev@googlegroups.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm, kasan: don't poison boot memory
Date: Thu, 18 Feb 2021 21:26:36 +0100 [thread overview]
Message-ID: <CAAeHK+yuvaYxjbfPwEeeh3mMa6_1hg=5LnjogxT2Vb1a-yiOmw@mail.gmail.com> (raw)
In-Reply-To: <509c1c80-bb2c-0c5c-ffa3-939ca40d2646@redhat.com>
On Thu, Feb 18, 2021 at 8:46 PM David Hildenbrand <david@redhat.com> wrote:
>
> > 1. For KASAN_GENERIC: leave everything as is to be able to detect
> > these boot-time bugs.
> >
> > 2. For KASAN_SW_TAGS: remove boot-time poisoning via
> > kasan_free_pages(), but use the "invalid" tag as the default shadow
> > value. The end result should be the same: bad accesses will be
> > detected. For unallocated memory as it has the default "invalid" tag,
> > and for allocated memory as it's poisoned properly when
> > allocated/freed.
> >
> > 3. For KASAN_HW_TAGS: just remove boot-time poisoning via
> > kasan_free_pages(). As the memory tags have a random unspecified
> > value, we'll still have a 15/16 chance to detect a memory corruption.
> >
> > This also makes sense from the performance perspective: KASAN_GENERIC
> > isn't meant to be running in production, so having a larger perf
> > impact is acceptable. The other two modes will be faster.
>
> Sounds in principle sane to me.
I'll post a v2 soon, thanks!
> Side note: I am not sure if anybody runs KASAN in production. Memory is
> expensive. Feel free to prove me wrong, I'd be very interest in actual
> users.
We run KASAN_SW_TAGS on some dogfood testing devices, and
KASAN_HW_TAGS is being developed with the goal to be running in
production.
next prev parent reply other threads:[~2021-02-18 20:26 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 20:56 [PATCH] mm, kasan: don't poison boot memory Andrey Konovalov
2021-02-18 8:55 ` David Hildenbrand
2021-02-18 19:40 ` Andrey Konovalov
2021-02-18 19:46 ` David Hildenbrand
2021-02-18 20:26 ` Andrey Konovalov [this message]
2021-02-19 0:06 ` George Kennedy
2021-02-19 0:09 ` Andrey Konovalov
2021-02-19 16:45 ` George Kennedy
2021-02-19 23:04 ` George Kennedy
2021-02-22 9:52 ` David Hildenbrand
2021-02-22 15:13 ` George Kennedy
2021-02-22 16:13 ` David Hildenbrand
2021-02-22 16:39 ` David Hildenbrand
2021-02-22 17:40 ` Konrad Rzeszutek Wilk
2021-02-22 18:45 ` Mike Rapoport
2021-02-22 18:42 ` George Kennedy
2021-02-22 21:55 ` Mike Rapoport
[not found] ` <9773282a-2854-25a4-9faa-9da5dd34e371@oracle.com>
2021-02-23 10:33 ` Mike Rapoport
[not found] ` <3ef9892f-d657-207f-d4cf-111f98dcb55c@oracle.com>
2021-02-23 15:47 ` Mike Rapoport
2021-02-23 18:05 ` George Kennedy
2021-02-23 20:09 ` Mike Rapoport
2021-02-23 21:16 ` George Kennedy
2021-02-23 21:32 ` Mike Rapoport
2021-02-23 21:46 ` George Kennedy
2021-02-24 10:37 ` Mike Rapoport
2021-02-24 14:22 ` George Kennedy
2021-02-25 8:53 ` Mike Rapoport
2021-02-25 12:38 ` George Kennedy
2021-02-25 14:57 ` Mike Rapoport
2021-02-25 15:22 ` George Kennedy
2021-02-25 16:06 ` George Kennedy
2021-02-25 16:07 ` Mike Rapoport
2021-02-25 16:31 ` George Kennedy
2021-02-25 17:23 ` David Hildenbrand
2021-02-25 17:41 ` Mike Rapoport
2021-02-25 17:50 ` Mike Rapoport
2021-02-25 17:33 ` George Kennedy
2021-02-26 1:19 ` George Kennedy
2021-02-26 11:17 ` Mike Rapoport
2021-02-26 16:16 ` George Kennedy
2021-02-28 18:08 ` Mike Rapoport
2021-03-01 14:29 ` George Kennedy
2021-03-02 1:20 ` George Kennedy
2021-03-02 9:57 ` Mike Rapoport
2021-02-23 21:26 ` George Kennedy
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