From mboxrd@z Thu Jan 1 00:00:00 1970 From: Walter Wu Subject: Re: [PATCH v4] kasan: add memory corruption identification for software tag-based mode Date: Thu, 22 Aug 2019 09:22:02 +0800 Message-ID: <1566436922.27117.0.camel@mtksdccf07> References: <20190806054340.16305-1-walter-zh.wu@mediatek.com> <1566279478.9993.21.camel@mtksdccf07> <3318f9d7-a760-3cc8-b700-f06108ae745f@virtuozzo.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <3318f9d7-a760-3cc8-b700-f06108ae745f@virtuozzo.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Andrey Ryabinin Cc: wsd_upstream@mediatek.com, Vasily Gorbik , Arnd Bergmann , linux-mm@kvack.org, Andrey Konovalov , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Martin Schwidefsky , Miles Chen , Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Matthias Brugger , linux-mediatek@lists.infradead.org, Andrew Morton , Thomas Gleixner , Dmitry Vyukov List-Id: linux-mediatek@lists.infradead.org On Wed, 2019-08-21 at 20:52 +0300, Andrey Ryabinin wrote: > > On 8/20/19 8:37 AM, Walter Wu wrote: > > On Tue, 2019-08-06 at 13:43 +0800, Walter Wu wrote: > >> This patch adds memory corruption identification at bug report for > >> software tag-based mode, the report show whether it is "use-after-free" > >> or "out-of-bound" error instead of "invalid-access" error. This will make > >> it easier for programmers to see the memory corruption problem. > >> > >> We extend the slab to store five old free pointer tag and free backtrace, > >> we can check if the tagged address is in the slab record and make a > >> good guess if the object is more like "use-after-free" or "out-of-bound". > >> therefore every slab memory corruption can be identified whether it's > >> "use-after-free" or "out-of-bound". > >> > >> ====== Changes > >> Change since v1: > >> - add feature option CONFIG_KASAN_SW_TAGS_IDENTIFY. > >> - change QUARANTINE_FRACTION to reduce quarantine size. > >> - change the qlist order in order to find the newest object in quarantine > >> - reduce the number of calling kmalloc() from 2 to 1 time. > >> - remove global variable to use argument to pass it. > >> - correct the amount of qobject cache->size into the byes of qlist_head. > >> - only use kasan_cache_shrink() to shink memory. > >> > >> Change since v2: > >> - remove the shinking memory function kasan_cache_shrink() > >> - modify the description of the CONFIG_KASAN_SW_TAGS_IDENTIFY > >> - optimize the quarantine_find_object() and qobject_free() > >> - fix the duplicating function name 3 times in the header. > >> - modify the function name set_track() to kasan_set_track() > >> > >> Change since v3: > >> - change tag-based quarantine to extend slab to identify memory corruption > > > > Hi,Andrey, > > > > Would you review the patch,please? > > > I didn't notice anything fundamentally wrong, but I find there are some > questionable implementation choices that makes code look weirder than necessary > and harder to understand. So I ended up with cleaning it up, see the diff bellow. > I'll send v5 with that diff folded. > Thanks your review and suggestion. Walter