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: 11156221 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 0BD2616B1 for ; Mon, 23 Sep 2019 08:21:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id CA10220835 for ; Mon, 23 Sep 2019 08:21:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CA10220835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id DF34E6B0007; Mon, 23 Sep 2019 04:21:04 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id DA4206B0008; Mon, 23 Sep 2019 04:21:04 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CB8056B000A; Mon, 23 Sep 2019 04:21:04 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0173.hostedemail.com [216.40.44.173]) by kanga.kvack.org (Postfix) with ESMTP id A66B56B0007 for ; Mon, 23 Sep 2019 04:21:04 -0400 (EDT) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 4D5AF8243763 for ; Mon, 23 Sep 2019 08:21:04 +0000 (UTC) X-FDA: 75965490048.01.ray39_7dae3fd922008 X-Spam-Summary: 1,0,0,,d41d8cd98f00b204,vbabka@suse.cz,:aryabinin@virtuozzo.com:walter-zh.wu@mediatek.com:cai@lca.pw:glider@google.com:dvyukov@google.com:matthias.bgg@gmail.com:akpm@linux-foundation.org:schwidefsky@de.ibm.com:andreyknvl@google.com:arnd@arndb.de:linux-kernel@vger.kernel.org:kasan-dev@googlegroups.com::linux-arm-kernel@lists.infradead.org:linux-mediatek@lists.infradead.org:wsd_upstream@mediatek.com,RULES_HIT:30054:30070:30090:30091,0,RBL:195.135.220.15:@suse.cz:.lbl8.mailshell.net-62.14.6.2 64.201.201.201,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:26,LUA_SUMMARY:none X-HE-Tag: ray39_7dae3fd922008 X-Filterd-Recvd-Size: 7329 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf41.hostedemail.com (Postfix) with ESMTP for ; Mon, 23 Sep 2019 08:21:03 +0000 (UTC) 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 Cc: Qian Cai , Alexander Potapenko , Dmitry Vyukov , Matthias Brugger , Andrew Morton , Martin Schwidefsky , Andrey Konovalov , Arnd Bergmann , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com 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-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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