From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FFCDC4CEC5 for ; Thu, 12 Sep 2019 15:14:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6F30B2084D for ; Thu, 12 Sep 2019 15:14:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6F30B2084D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=mediatek.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 065246B0005; Thu, 12 Sep 2019 11:14:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0159D6B0006; Thu, 12 Sep 2019 11:14:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E6E266B0007; Thu, 12 Sep 2019 11:14:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0190.hostedemail.com [216.40.44.190]) by kanga.kvack.org (Postfix) with ESMTP id C69556B0005 for ; Thu, 12 Sep 2019 11:14:01 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id 605471E099 for ; Thu, 12 Sep 2019 15:14:01 +0000 (UTC) X-FDA: 75926613882.12.noise66_22f31c280ea4a X-HE-Tag: noise66_22f31c280ea4a X-Filterd-Recvd-Size: 4475 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Thu, 12 Sep 2019 15:13:59 +0000 (UTC) X-UUID: 1573f0ea1df94009b360989531af66db-20190912 X-UUID: 1573f0ea1df94009b360989531af66db-20190912 Received: from mtkcas06.mediatek.inc [(172.21.101.30)] by mailgw02.mediatek.com (envelope-from ) (Cellopoint E-mail Firewall v4.1.10 Build 0809 with TLS) with ESMTP id 415036316; Thu, 12 Sep 2019 23:13:55 +0800 Received: from mtkcas08.mediatek.inc (172.21.101.126) by mtkmbs07n1.mediatek.inc (172.21.101.16) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Thu, 12 Sep 2019 23:13:53 +0800 Received: from [172.21.84.99] (172.21.84.99) by mtkcas08.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Thu, 12 Sep 2019 23:13:52 +0800 Message-ID: <1568301233.19274.17.camel@mtksdccf07> Subject: Re: [PATCH v3] mm/kasan: dump alloc and free stack for page allocator From: Walter Wu To: Vlastimil Babka CC: Qian Cai , Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , "Andrew Morton" , Martin Schwidefsky , Andrey Konovalov , "Arnd Bergmann" , , , , , , Date: Thu, 12 Sep 2019 23:13:53 +0800 In-Reply-To: <613f9f23-c7f0-871f-fe13-930c35ef3105@suse.cz> References: <20190911083921.4158-1-walter-zh.wu@mediatek.com> <5E358F4B-552C-4542-9655-E01C7B754F14@lca.pw> <1568297308.19040.5.camel@mtksdccf07> <613f9f23-c7f0-871f-fe13-930c35ef3105@suse.cz> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 Content-Transfer-Encoding: 7bit MIME-Version: 1.0 X-MTK: N X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, 2019-09-12 at 16:31 +0200, Vlastimil Babka wrote: > On 9/12/19 4:08 PM, Walter Wu wrote: > > > >> extern void __reset_page_owner(struct page *page, unsigned int order); > >> diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan > >> index 6c9682ce0254..dc560c7562e8 100644 > >> --- a/lib/Kconfig.kasan > >> +++ b/lib/Kconfig.kasan > >> @@ -41,6 +41,8 @@ config KASAN_GENERIC > >> select SLUB_DEBUG if SLUB > >> select CONSTRUCTORS > >> select STACKDEPOT > >> + select PAGE_OWNER > >> + select PAGE_OWNER_FREE_STACK > >> help > >> Enables generic KASAN mode. > >> Supported in both GCC and Clang. With GCC it requires version 4.9.2 > >> @@ -63,6 +65,8 @@ config KASAN_SW_TAGS > >> select SLUB_DEBUG if SLUB > >> select CONSTRUCTORS > >> select STACKDEPOT > >> + select PAGE_OWNER > >> + select PAGE_OWNER_FREE_STACK > >> help > > > > What is the difference between PAGE_OWNER+PAGE_OWNER_FREE_STACK and > > DEBUG_PAGEALLOC? > > Same memory usage, but debug_pagealloc means also extra checks and > restricting memory access to freed pages to catch UAF. > > > If you directly enable PAGE_OWNER+PAGE_OWNER_FREE_STACK > > PAGE_OWNER_FREE_STACK,don't you think low-memory device to want to use > > KASAN? > > OK, so it should be optional? But I think it's enough to distinguish no > PAGE_OWNER at all, and PAGE_OWNER+PAGE_OWNER_FREE_STACK together - I > don't see much point in PAGE_OWNER only for this kind of debugging. > If it's possible, it should be optional. My experience is that PAGE_OWNER usually debug memory leakage. > So how about this? KASAN wouldn't select PAGE_OWNER* but it would be > recommended in the help+docs. When PAGE_OWNER and KASAN are selected by > user, PAGE_OWNER_FREE_STACK gets also selected, and both will be also > runtime enabled without explicit page_owner=on. > I mostly want to avoid another boot-time option for enabling > PAGE_OWNER_FREE_STACK. > Would that be enough flexibility for low-memory devices vs full-fledged > debugging? We usually see feature option to decide whether it meet the platform. The boot-time option isn't troubled to us, because enable the feature owner should know what he should add to do.