From: Daniel Axtens <dja@axtens.net>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
kasan-dev@googlegroups.com, linux-mm@kvack.org, x86@kernel.org,
glider@google.com, luto@kernel.org, linux-kernel@vger.kernel.org,
dvyukov@google.com, christophe.leroy@c-s.fr,
linuxppc-dev@lists.ozlabs.org, gor@linux.ibm.com
Subject: Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory
Date: Tue, 15 Oct 2019 17:32:03 +1100 [thread overview]
Message-ID: <875zkqtt7g.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <20191014152717.GA20438@lakrids.cambridge.arm.com>
> There is a potential problem here, as Will Deacon wrote up at:
>
> https://lore.kernel.org/linux-arm-kernel/20190827131818.14724-1-will@kernel.org/
>
> ... in the section starting:
>
> | *** Other architecture maintainers -- start here! ***
>
> ... whereby the CPU can spuriously fault on an access after observing a
> valid PTE.
>
> For arm64 we handle the spurious fault, and it looks like x86 would need
> something like its vmalloc_fault() applying to the shadow region to
> cater for this.
I'm not really up on x86 - my first thought would be that their stronger
memory ordering might be sufficient but I really don't know. Reading the
thread I see arm and powerpc discussions but nothing from anyone else,
so I'm none the wiser there...
Andy, do you have any thoughts?
Regards,
Daniel
>
> Thanks,
> Mark.
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Axtens <dja@axtens.net>
To: Mark Rutland <mark.rutland@arm.com>
Cc: gor@linux.ibm.com, x86@kernel.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
glider@google.com, luto@kernel.org,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
linuxppc-dev@lists.ozlabs.org, dvyukov@google.com
Subject: Re: [PATCH v8 1/5] kasan: support backing vmalloc space with real shadow memory
Date: Tue, 15 Oct 2019 17:32:03 +1100 [thread overview]
Message-ID: <875zkqtt7g.fsf@dja-thinkpad.axtens.net> (raw)
In-Reply-To: <20191014152717.GA20438@lakrids.cambridge.arm.com>
> There is a potential problem here, as Will Deacon wrote up at:
>
> https://lore.kernel.org/linux-arm-kernel/20190827131818.14724-1-will@kernel.org/
>
> ... in the section starting:
>
> | *** Other architecture maintainers -- start here! ***
>
> ... whereby the CPU can spuriously fault on an access after observing a
> valid PTE.
>
> For arm64 we handle the spurious fault, and it looks like x86 would need
> something like its vmalloc_fault() applying to the shadow region to
> cater for this.
I'm not really up on x86 - my first thought would be that their stronger
memory ordering might be sufficient but I really don't know. Reading the
thread I see arm and powerpc discussions but nothing from anyone else,
so I'm none the wiser there...
Andy, do you have any thoughts?
Regards,
Daniel
>
> Thanks,
> Mark.
next prev parent reply other threads:[~2019-10-15 6:32 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-01 6:58 [PATCH v8 0/5] kasan: support backing vmalloc space with real shadow memory Daniel Axtens
2019-10-01 6:58 ` [PATCH v8 1/5] " Daniel Axtens
2019-10-01 10:17 ` Uladzislau Rezki
2019-10-01 10:17 ` Uladzislau Rezki
2019-10-02 1:23 ` Daniel Axtens
2019-10-02 1:23 ` Daniel Axtens
2019-10-02 7:13 ` Christophe Leroy
2019-10-02 7:13 ` Christophe Leroy
2019-10-02 11:49 ` Uladzislau Rezki
2019-10-02 11:49 ` Uladzislau Rezki
2019-10-07 8:02 ` Uladzislau Rezki
2019-10-07 8:02 ` Uladzislau Rezki
2019-10-11 5:15 ` Daniel Axtens
2019-10-11 5:15 ` Daniel Axtens
2019-10-11 19:57 ` Andrey Ryabinin
2019-10-14 13:57 ` Daniel Axtens
2019-10-14 15:27 ` Mark Rutland
2019-10-14 15:27 ` Mark Rutland
2019-10-15 6:32 ` Daniel Axtens [this message]
2019-10-15 6:32 ` Daniel Axtens
2019-10-15 6:29 ` Daniel Axtens
2019-10-16 12:19 ` Andrey Ryabinin
2019-10-16 13:22 ` Mark Rutland
2019-10-16 13:22 ` Mark Rutland
2019-10-18 10:43 ` Andrey Ryabinin
2019-10-18 10:43 ` Andrey Ryabinin
2019-10-28 7:39 ` Daniel Axtens
2019-10-28 7:39 ` Daniel Axtens
2019-10-28 1:26 ` Daniel Axtens
2019-10-28 1:26 ` Daniel Axtens
2019-10-14 15:43 ` Mark Rutland
2019-10-14 15:43 ` Mark Rutland
2019-10-15 6:27 ` Daniel Axtens
2019-10-15 6:27 ` Daniel Axtens
2019-10-01 6:58 ` [PATCH v8 2/5] kasan: add test for vmalloc Daniel Axtens
2019-10-01 6:58 ` [PATCH v8 3/5] fork: support VMAP_STACK with KASAN_VMALLOC Daniel Axtens
2019-10-01 6:58 ` [PATCH v8 4/5] x86/kasan: support KASAN_VMALLOC Daniel Axtens
2019-10-01 6:58 ` [PATCH v8 5/5] kasan debug: track pages allocated for vmalloc shadow Daniel Axtens
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