From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f41.google.com (mail-pa0-f41.google.com [209.85.220.41]) by kanga.kvack.org (Postfix) with ESMTP id DEE2D6B0035 for ; Thu, 10 Jul 2014 11:58:16 -0400 (EDT) Received: by mail-pa0-f41.google.com with SMTP id fb1so11414343pad.0 for ; Thu, 10 Jul 2014 08:58:16 -0700 (PDT) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id zy5si48866082pbc.35.2014.07.10.08.58.12 for ; Thu, 10 Jul 2014 08:58:13 -0700 (PDT) Message-ID: <53BEB77A.6020003@intel.com> Date: Thu, 10 Jul 2014 08:55:38 -0700 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [RFC/PATCH RESEND -next 01/21] Add kernel address sanitizer infrastructure. References: <1404905415-9046-1-git-send-email-a.ryabinin@samsung.com> <1404905415-9046-2-git-send-email-a.ryabinin@samsung.com> <53BDA568.5030607@intel.com> <53BE8333.6060404@samsung.com> In-Reply-To: <53BE8333.6060404@samsung.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrey Ryabinin , linux-kernel@vger.kernel.org Cc: Dmitry Vyukov , Konstantin Serebryany , Alexey Preobrazhensky , Andrey Konovalov , Yuri Gribov , Konstantin Khlebnikov , Sasha Levin , Michal Marek , Russell King , Thomas Gleixner , Ingo Molnar , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , linux-kbuild@vger.kernel.org, linux-arm-kernel@lists.infradead.org, x86@kernel.org, linux-mm@kvack.org On 07/10/2014 05:12 AM, Andrey Ryabinin wrote: > On 07/10/14 00:26, Dave Hansen wrote: >> On 07/09/2014 04:29 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 - PAGE_OFFSET) >> KASAN_SHADOW_SCALE_SHIFT) >>> + kasan_shadow_start; >>> } >> >> How does this interact with vmalloc() addresses or those from a kmap()? >> > It's used only for lowmem: > > static inline bool addr_is_in_mem(unsigned long addr) > { > return likely(addr >= PAGE_OFFSET && addr < (unsigned long)high_memory); > } That's fine, and definitely covers the common cases. Could you make sure to call this out explicitly? Also, there's nothing to _keep_ this approach working for things out of the direct map, right? It would just be a matter of updating the shadow memory to have entries for the other virtual address ranges. addr_is_in_mem() is a pretty bad name for what it's doing. :) I'd probably call it something like kasan_tracks_vaddr(). -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org