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From: Andy Lutomirski <luto@amacapital.net>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
	X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
	Brian Gerst <brgerst@gmail.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] x86/kasan: clear kasan_zero_page after TLB flush
Date: Mon, 18 Jan 2016 14:24:06 -0800	[thread overview]
Message-ID: <CALCETrUJfc10=gGPYruw8MLvAGm+5VKP2bj8ex1Y=oXaMUA6Jg@mail.gmail.com> (raw)
In-Reply-To: <1452516679-32040-2-git-send-email-aryabinin@virtuozzo.com>

On Mon, Jan 11, 2016 at 4:51 AM, Andrey Ryabinin
<aryabinin@virtuozzo.com> wrote:
> Currently we clear kasan_zero_page before __flush_tlb_all(). This
> works with current implementation of native_flush_tlb[_global]()
> because it doesn't cause do any writes to kasan shadow memory.
> But any subtle change made in native_flush_tlb*() could break this.
> Also current code seems doesn't work for paravirt guests (lguest).
>
> Only after the TLB flush we can be sure that kasan_zero_page is not
> used as early shadow anymore (instrumented code will not write to it).
> So it should cleared it only after the TLB flush.

This seems to fix the issue with my patch set.  Thanks.

Tested-by: Andy Lutomirski <luto@kernel.org>

--Andy

  reply	other threads:[~2016-01-18 22:24 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-08 23:15 [RFC 00/13] x86/mm: PCID and INVPCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 01/13] x86/paravirt: Turn KASAN off for parvirt.o Andy Lutomirski
2016-01-10 18:59   ` Borislav Petkov
2016-01-11 12:51     ` Andrey Ryabinin
2016-01-11 12:51       ` [PATCH 1/2] x86/kasan: clear kasan_zero_page after TLB flush Andrey Ryabinin
2016-01-18 22:24         ` Andy Lutomirski [this message]
2016-02-09 16:06         ` [tip:x86/mm] x86/kasan: Clear " tip-bot for Andrey Ryabinin
2016-01-11 12:51       ` [PATCH 2/2] x86/kasan: write protect kasan zero shadow Andrey Ryabinin
2016-01-18 22:24         ` Andy Lutomirski
2016-02-09 16:07         ` [tip:x86/mm] x86/kasan: Write " tip-bot for Andrey Ryabinin
2016-01-29 10:35       ` [RFC 01/13] x86/paravirt: Turn KASAN off for parvirt.o Borislav Petkov
2016-01-08 23:15 ` [RFC 02/13] x86/mm: Add INVPCID helpers Andy Lutomirski
2016-01-08 23:15 ` [RFC 03/13] x86/mm: Add a noinvpcid option to turn off INVPCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 04/13] x86/mm: If INVPCID is available, use it to flush global mappings Andy Lutomirski
2016-01-08 23:15 ` [RFC 05/13] x86/mm: Add barriers and document switch_mm-vs-flush synchronization Andy Lutomirski
2016-06-03 17:42   ` Nadav Amit
2016-06-09 17:24     ` Andy Lutomirski
2016-06-09 19:45       ` Nadav Amit
2016-09-06  1:22   ` Wanpeng Li
2016-01-08 23:15 ` [RFC 06/13] x86/mm: Disable PCID on 32-bit kernels Andy Lutomirski
2016-01-08 23:15 ` [RFC 07/13] x86/mm: Add nopcid to turn off PCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 08/13] x86/mm: Teach CR3 readers about PCID Andy Lutomirski
2016-01-08 23:15 ` [RFC 09/13] x86/mm: Disable interrupts when flushing the TLB using CR3 Andy Lutomirski
2016-01-08 23:41   ` Linus Torvalds
2016-01-09  0:18     ` Andy Lutomirski
2016-01-09  2:20       ` Linus Torvalds
2016-01-11 10:51         ` Ingo Molnar
2016-01-13 23:32           ` Andy Lutomirski
2016-01-13 23:35         ` Andy Lutomirski
2016-01-13 23:43           ` Dave Hansen
2016-01-13 23:51             ` Andy Lutomirski
2016-01-13 23:56               ` Dave Hansen
2016-01-14  0:34                 ` Andy Lutomirski
2016-01-08 23:15 ` [RFC 10/13] x86/mm: Factor out remote TLB flushing Andy Lutomirski
2016-01-08 23:15 ` [RFC 11/13] x86/mm: Build arch/x86/mm/tlb.c even on !SMP Andy Lutomirski
2016-01-08 23:55   ` Dave Hansen
2016-01-08 23:15 ` [RFC 12/13] x86/mm: Uninline switch_mm Andy Lutomirski
2016-01-08 23:15 ` [RFC 13/13] x86/mm: Try to preserve old TLB entries using PCID Andy Lutomirski
2016-01-09  0:27   ` Dave Hansen
2016-01-09  2:19     ` Andy Lutomirski
2016-01-08 23:31 ` [RFC 00/13] x86/mm: PCID and INVPCID Linus Torvalds
2016-01-08 23:36   ` Andy Lutomirski
2016-01-08 23:42     ` Linus Torvalds

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