From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrey Ryabinin <a.ryabinin@samsung.com>, linux-kernel@vger.kernel.org
Cc: Dmitry Vyukov <dvyukov@google.com>,
Konstantin Serebryany <kcc@google.com>,
Alexey Preobrazhensky <preobr@google.com>,
Andrey Konovalov <adech.fo@gmail.com>,
Yuri Gribov <tetra2005@gmail.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Sasha Levin <sasha.levin@oracle.com>,
Michal Marek <mmarek@suse.cz>,
Russell King <linux@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kbuild@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, x86@kernel.org,
linux-mm@kvack.org
Subject: Re: [RFC/PATCH -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector.
Date: Fri, 11 Jul 2014 17:59:34 -0700 [thread overview]
Message-ID: <53C08876.10209@zytor.com> (raw)
In-Reply-To: <1404903678-8257-1-git-send-email-a.ryabinin@samsung.com>
On 07/09/2014 04:00 AM, Andrey Ryabinin wrote:
>
> Address sanitizer dedicates 1/8 of the low memory to the shadow memory and uses direct
> mapping with a scale and offset to translate a memory address to its corresponding
> shadow address.
>
> Here is function to translate address to corresponding shadow address:
>
> unsigned long kasan_mem_to_shadow(unsigned long addr)
> {
> return ((addr) >> KASAN_SHADOW_SCALE_SHIFT)
> + kasan_shadow_start - (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT);
> }
>
> where KASAN_SHADOW_SCALE_SHIFT = 3.
>
How does that work when memory is sparsely populated?
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: hpa@zytor.com (H. Peter Anvin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC/PATCH -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector.
Date: Fri, 11 Jul 2014 17:59:34 -0700 [thread overview]
Message-ID: <53C08876.10209@zytor.com> (raw)
In-Reply-To: <1404903678-8257-1-git-send-email-a.ryabinin@samsung.com>
On 07/09/2014 04:00 AM, Andrey Ryabinin wrote:
>
> Address sanitizer dedicates 1/8 of the low memory to the shadow memory and uses direct
> mapping with a scale and offset to translate a memory address to its corresponding
> shadow address.
>
> Here is function to translate address to corresponding shadow address:
>
> unsigned long kasan_mem_to_shadow(unsigned long addr)
> {
> return ((addr) >> KASAN_SHADOW_SCALE_SHIFT)
> + kasan_shadow_start - (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT);
> }
>
> where KASAN_SHADOW_SCALE_SHIFT = 3.
>
How does that work when memory is sparsely populated?
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Andrey Ryabinin <a.ryabinin@samsung.com>, linux-kernel@vger.kernel.org
Cc: Dmitry Vyukov <dvyukov@google.com>,
Konstantin Serebryany <kcc@google.com>,
Alexey Preobrazhensky <preobr@google.com>,
Andrey Konovalov <adech.fo@gmail.com>,
Yuri Gribov <tetra2005@gmail.com>,
Konstantin Khlebnikov <koct9i@gmail.com>,
Sasha Levin <sasha.levin@oracle.com>,
Michal Marek <mmarek@suse.cz>,
Russell King <linux@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kbuild@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, x86@kernel.org,
linux-mm@kvack.org
Subject: Re: [RFC/PATCH -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector.
Date: Fri, 11 Jul 2014 17:59:34 -0700 [thread overview]
Message-ID: <53C08876.10209@zytor.com> (raw)
In-Reply-To: <1404903678-8257-1-git-send-email-a.ryabinin@samsung.com>
On 07/09/2014 04:00 AM, Andrey Ryabinin wrote:
>
> Address sanitizer dedicates 1/8 of the low memory to the shadow memory and uses direct
> mapping with a scale and offset to translate a memory address to its corresponding
> shadow address.
>
> Here is function to translate address to corresponding shadow address:
>
> unsigned long kasan_mem_to_shadow(unsigned long addr)
> {
> return ((addr) >> KASAN_SHADOW_SCALE_SHIFT)
> + kasan_shadow_start - (PAGE_OFFSET >> KASAN_SHADOW_SCALE_SHIFT);
> }
>
> where KASAN_SHADOW_SCALE_SHIFT = 3.
>
How does that work when memory is sparsely populated?
-hpa
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next prev parent reply other threads:[~2014-07-12 1:00 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-09 11:00 [RFC/PATCH -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector Andrey Ryabinin
2014-07-09 11:00 ` Andrey Ryabinin
2014-07-09 11:00 ` Andrey Ryabinin
2014-07-09 11:00 ` [RFC/PATCH -next 01/21] Add kernel address sanitizer infrastructure Andrey Ryabinin
2014-07-09 11:00 ` [RFC/PATCH -next 02/21] init: main: initialize kasan's shadow area on boot Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 03/21] x86: add kasan hooks fort memcpy/memmove/memset functions Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 04/21] x86: boot: vdso: disable instrumentation for code not linked with kernel Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 05/21] x86: cpu: don't sanitize early stages of a secondary CPU boot Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 06/21] x86: mm: init: allocate shadow memory for kasan Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 07/21] x86: Kconfig: enable kernel address sanitizer Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 08/21] mm: page_alloc: add kasan hooks on alloc and free pathes Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 09/21] mm: Makefile: kasan: don't instrument slub.c and slab_common.c files Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 10/21] mm: slab: share virt_to_cache() between slab and slub Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 11/21] mm: slub: share slab_err and object_err functions Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 12/21] mm: util: move krealloc/kzfree to slab_common.c Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 13/21] mm: slub: add allocation size field to struct kmem_cache Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 14/21] mm: slub: kasan: disable kasan when touching unaccessible memory Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 15/21] mm: slub: add kernel address sanitizer hooks to slub allocator Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 16/21] arm: boot: compressed: disable kasan's instrumentation Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 17/21] arm: add kasan hooks fort memcpy/memmove/memset functions Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 18/21] arm: mm: reserve shadow memory for kasan Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 19/21] arm: Kconfig: enable kernel address sanitizer Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 20/21] fs: dcache: manually unpoison dname after allocation to shut up kasan's reports Andrey Ryabinin
2014-07-09 11:01 ` [RFC/PATCH -next 21/21] lib: add kmalloc_bug_test module Andrey Ryabinin
2014-07-12 0:59 ` H. Peter Anvin [this message]
2014-07-12 0:59 ` [RFC/PATCH -next 00/21] Address sanitizer for kernel (kasan) - dynamic memory error detector H. Peter Anvin
2014-07-12 0:59 ` H. Peter Anvin
2014-07-13 10:39 ` Andrey Ryabinin
2014-07-13 10:39 ` Andrey Ryabinin
2014-07-13 10:39 ` Andrey Ryabinin
2014-07-14 15:13 ` Christoph Lameter
2014-07-14 15:13 ` Christoph Lameter
2014-07-14 15:13 ` Christoph Lameter
2014-07-15 14:32 ` Andrey Ryabinin
2014-07-15 14:32 ` Andrey Ryabinin
2014-07-15 14:32 ` Andrey Ryabinin
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