From patchwork Mon Sep 23 08:20:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vlastimil Babka X-Patchwork-Id: 11156223 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B02E016B1 for ; Mon, 23 Sep 2019 08:21:12 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8E4E820882 for ; Mon, 23 Sep 2019 08:21:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="BjK5/t1P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8E4E820882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date: Message-ID:From:References:To:Subject:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Cd5uxBZi8WSE2YC0CWnPbFFd1oyQpdVnM+DmzYeo4/k=; b=BjK5/t1PIDlsMo qDMyypXUeJJxWTo9j5RTdZMBZBCX4J7u8CoSCubI2sGBwufL1GJy65dqsQ6TUnKkuToAe3wSShSc7 ugIoRhl9claLKKHgQDK2BYue6uOLD8iIcChhoMU1RM0vBGHW4UJ3Amlh66uU7Tf675PDiudYQVTVq QuLndn30Eq1s6Jfkwapxl89h2tEwGtyC4OHq25VwSBbd8olMIxHoqFUbwVQbeZizVvpzUoIe2dtPY AuO8XkPtMOhK/vL7QmV+NPsYRyyyllaXhZ1rcE0I5Tc8eRIzM4Ah5Gyrw/rpYLR6WnQ313QquQbqT a+H0QqlmSMwPc+MIS8+A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iCJao-00029W-Vl; Mon, 23 Sep 2019 08:21:10 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1iCJak-00028O-70; Mon, 23 Sep 2019 08:21:09 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 1B798ACE3; Mon, 23 Sep 2019 08:21:01 +0000 (UTC) Subject: [PATCH] mm, debug, kasan: save and dump freeing stack trace for kasan To: Andrey Ryabinin , Walter Wu 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> <79fede05-735b-8477-c273-f34db93fd72b@virtuozzo.com> <6d58ce86-b2a4-40af-bf40-c604b457d086@suse.cz> <4e76e7ce-1d61-524a-622b-663c01d19707@virtuozzo.com> From: Vlastimil Babka Message-ID: Date: Mon, 23 Sep 2019 10:20:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <4e76e7ce-1d61-524a-622b-663c01d19707@virtuozzo.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190923_012106_542906_7D1AAAE1 X-CRM114-Status: GOOD ( 19.14 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [195.135.220.15 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wsd_upstream@mediatek.com, Arnd Bergmann , linux-mm@kvack.org, Andrey Konovalov , linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, Martin Schwidefsky , Alexander Potapenko , linux-arm-kernel@lists.infradead.org, Matthias Brugger , Qian Cai , Andrew Morton , Dmitry Vyukov Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org On 9/16/19 5:57 PM, Andrey Ryabinin wrote: > I'd rather keep all logic in one place, i.e. "if (!page_owner_disabled && (IS_ENABLED(CONFIG_KASAN) || debug_pagealloc_enabled())" > With this no changes in early_debug_pagealloc() required and CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT=y should also work correctly. OK. ----8<---- From 7437c43f02682fdde5680fa83e87029f7529e222 Mon Sep 17 00:00:00 2001 From: Vlastimil Babka Date: Mon, 16 Sep 2019 11:28:19 +0200 Subject: [PATCH] mm, debug, kasan: save and dump freeing stack trace for kasan The commit "mm, page_owner, debug_pagealloc: save and dump freeing stack trace" enhanced page_owner to also store freeing stack trace, when debug_pagealloc is also enabled. KASAN would also like to do this [1] to improve error reports to debug e.g. UAF issues. This patch therefore introduces a helper config option PAGE_OWNER_FREE_STACK, which is enabled when PAGE_OWNER and either of DEBUG_PAGEALLOC or KASAN is enabled. Boot-time, the free stack saving is enabled when booting a KASAN kernel with page_owner=on, or non-KASAN kernel with debug_pagealloc=on and page_owner=on. [1] https://bugzilla.kernel.org/show_bug.cgi?id=203967 Suggested-by: Dmitry Vyukov Suggested-by: Walter Wu Suggested-by: Andrey Ryabinin Signed-off-by: Vlastimil Babka Reviewed-by: Andrey Ryabinin --- Documentation/dev-tools/kasan.rst | 4 ++++ mm/Kconfig.debug | 4 ++++ mm/page_owner.c | 31 ++++++++++++++++++------------- 3 files changed, 26 insertions(+), 13 deletions(-) diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index b72d07d70239..434e605030e9 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -41,6 +41,10 @@ smaller binary while the latter is 1.1 - 2 times faster. Both KASAN modes work with both SLUB and SLAB memory allocators. For better bug detection and nicer reporting, enable CONFIG_STACKTRACE. +To augment reports with last allocation and freeing stack of the physical +page, it is recommended to configure kernel also with CONFIG_PAGE_OWNER = y +and boot with page_owner=on. + To disable instrumentation for specific files or directories, add a line similar to the following to the respective kernel Makefile: diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug index 327b3ebf23bf..1ea247da3322 100644 --- a/mm/Kconfig.debug +++ b/mm/Kconfig.debug @@ -62,6 +62,10 @@ config PAGE_OWNER If unsure, say N. +config PAGE_OWNER_FREE_STACK + def_bool KASAN || DEBUG_PAGEALLOC + depends on PAGE_OWNER + config PAGE_POISONING bool "Poison pages after freeing" select PAGE_POISONING_NO_SANITY if HIBERNATION diff --git a/mm/page_owner.c b/mm/page_owner.c index dee931184788..8b6b05676158 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -24,13 +24,14 @@ struct page_owner { short last_migrate_reason; gfp_t gfp_mask; depot_stack_handle_t handle; -#ifdef CONFIG_DEBUG_PAGEALLOC +#ifdef CONFIG_PAGE_OWNER_FREE_STACK depot_stack_handle_t free_handle; #endif }; static bool page_owner_disabled = true; DEFINE_STATIC_KEY_FALSE(page_owner_inited); +static DEFINE_STATIC_KEY_FALSE(page_owner_free_stack); static depot_stack_handle_t dummy_handle; static depot_stack_handle_t failure_handle; @@ -91,6 +92,8 @@ static void init_page_owner(void) register_failure_stack(); register_early_stack(); static_branch_enable(&page_owner_inited); + if (IS_ENABLED(CONFIG_KASAN) || debug_pagealloc_enabled()) + static_branch_enable(&page_owner_free_stack); init_early_allocated_pages(); } @@ -148,11 +151,11 @@ void __reset_page_owner(struct page *page, unsigned int order) { int i; struct page_ext *page_ext; -#ifdef CONFIG_DEBUG_PAGEALLOC +#ifdef CONFIG_PAGE_OWNER_FREE_STACK depot_stack_handle_t handle = 0; struct page_owner *page_owner; - if (debug_pagealloc_enabled()) + if (static_branch_unlikely(&page_owner_free_stack)) handle = save_stack(GFP_NOWAIT | __GFP_NOWARN); #endif @@ -161,8 +164,8 @@ void __reset_page_owner(struct page *page, unsigned int order) if (unlikely(!page_ext)) continue; __clear_bit(PAGE_EXT_OWNER_ACTIVE, &page_ext->flags); -#ifdef CONFIG_DEBUG_PAGEALLOC - if (debug_pagealloc_enabled()) { +#ifdef CONFIG_PAGE_OWNER_FREE_STACK + if (static_branch_unlikely(&page_owner_free_stack)) { page_owner = get_page_owner(page_ext); page_owner->free_handle = handle; } @@ -451,14 +454,16 @@ void __dump_page_owner(struct page *page) stack_trace_print(entries, nr_entries, 0); } -#ifdef CONFIG_DEBUG_PAGEALLOC - handle = READ_ONCE(page_owner->free_handle); - if (!handle) { - pr_alert("page_owner free stack trace missing\n"); - } else { - nr_entries = stack_depot_fetch(handle, &entries); - pr_alert("page last free stack trace:\n"); - stack_trace_print(entries, nr_entries, 0); +#ifdef CONFIG_PAGE_OWNER_FREE_STACK + if (static_branch_unlikely(&page_owner_free_stack)) { + handle = READ_ONCE(page_owner->free_handle); + if (!handle) { + pr_alert("page_owner free stack trace missing\n"); + } else { + nr_entries = stack_depot_fetch(handle, &entries); + pr_alert("page last free stack trace:\n"); + stack_trace_print(entries, nr_entries, 0); + } } #endif