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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 566B0C4CEC5 for ; Thu, 12 Sep 2019 14:10:32 +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 2B2752053B for ; Thu, 12 Sep 2019 14:10:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="E3+y1+t4"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="IPApOKeT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B2752053B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.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:Mime-Version:References:In-Reply-To: Date:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=3/pMaq6FLhhjSDzVhOEELRk20+kvx6//9pZV3SNw2ic=; b=E3+y1+t4+FZWPU ji+9mhSXUik1EYE943E+PkmMK4f7CpttqgkfbR7rv/OSq4Qxex7vEk6WSb2d/8lM65PARBO2TovgA gZ2N/FBNvc1OvsQeSul8RMpufZQK1536GlKoAIsfUl3b8fif8RD/F65UCw/cpxGH17hc8wpVLhRND 6qiq6ZNKIAo0QRzQ+pQImnqeM7QzZmnAerPyQP8hZphFRM8vBJUJBZK8VxwYlp7Xj9gqajDh3H5CX vszunVD/RSBzt0QQ+xJw/SM64NkXzvpdkkkuO4xQMf5lYd1Wfm4yTbdqkzs+7md7WJ/kvexjT9uQF ZcUjwbY9ISEA7zQ1CXsQ==; 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 1i8Pnj-0004IC-Ol; Thu, 12 Sep 2019 14:10:23 +0000 Received: from mail-qk1-x743.google.com ([2607:f8b0:4864:20::743]) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1i8Png-0004H1-QS for linux-arm-kernel@lists.infradead.org; Thu, 12 Sep 2019 14:10:22 +0000 Received: by mail-qk1-x743.google.com with SMTP id 4so24569626qki.6 for ; Thu, 12 Sep 2019 07:10:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=GCjjLgVtFgvLpF7hk0kQsXY9fbLxlC94ZIxVciM5Jrc=; b=IPApOKeTDA0Q9+airIUTSKgoI5W/B0vmtx4ONsYipmEFXipYHSjxhseubVsD78TdxU dYPV78ZTBxTrnu/tMf4HVQMXSw8U6dt1SmhrJ5a19zxDaakP7L+QesLii21nf2FzPHxN Zjs6ekynBLAGjgTMoM4zHhBJSE+7E0uuU9piEVI+bjaJelgfjRJ2H5j39IXm4yv9xI6E esqYGbyoNBcgomaPf9V0h7s54HaVzL3i3U6i1O2S3WrEAdaJPEAP5jG8h8sM1lHIIYlF XUKbgoOWnroOIHvP3QjURsVtfoTrXmohsNBtw/UBWrHLW5ESORYaXQpvpiIG0kHvSIx9 2XdA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:mime-version:content-transfer-encoding; bh=GCjjLgVtFgvLpF7hk0kQsXY9fbLxlC94ZIxVciM5Jrc=; b=FKPJqVZaqfdqUaiXhvDj9p3ZZxvOoo28tu6wYmgY6nKwnqaAMMVqAp1XKdVtr/ed56 puiWuia8BZpDqTocy0QLFz/IYmvYwiWKXoyZNmXOydOhooF/GBYvt8nzwOM6BphbL8vg Ou1VfXlWeyN1tfmUb+fh33eYaIvyFzjjouDbps/QZ7jG7dNjrOqDqJLehRip35KgzCxl qQ57290QmXLEtHWmPxsZK0ODVWyPT1aRY01GnrdOInyNVkeu9NQSt0msHpoCmDK/Zzco qg++/GE1GRVqLbEmDyxj1307p/osTzPgAd74BnaK08sUg4q0nS5vTaOnM2v7mfF4gLjG Sc/g== X-Gm-Message-State: APjAAAVZZsL/nOKug5WQnK+DnNbmtDnT2tOecls5ea86z5/eE3CBszzX xeK+wrGWq+Nymimh3a6nFMh63w== X-Google-Smtp-Source: APXvYqxQUvfIMWnP584+jxyb55PV/oXt+R5gYyiqrvmNhItO9b00LDpKMRkbSIi9+vN3Gj5tiYCd3w== X-Received: by 2002:a37:aa96:: with SMTP id t144mr29539420qke.275.1568297418177; Thu, 12 Sep 2019 07:10:18 -0700 (PDT) Received: from dhcp-41-57.bos.redhat.com (nat-pool-bos-t.redhat.com. [66.187.233.206]) by smtp.gmail.com with ESMTPSA id i4sm6615004qke.93.2019.09.12.07.10.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 12 Sep 2019 07:10:17 -0700 (PDT) Message-ID: <1568297415.5576.143.camel@lca.pw> Subject: Re: [PATCH v3] mm/kasan: dump alloc and free stack for page allocator From: Qian Cai To: Vlastimil Babka , Walter Wu Date: Thu, 12 Sep 2019 10:10:15 -0400 In-Reply-To: References: <20190911083921.4158-1-walter-zh.wu@mediatek.com> <5E358F4B-552C-4542-9655-E01C7B754F14@lca.pw> X-Mailer: Evolution 3.22.6 (3.22.6-10.el7) Mime-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190912_071020_864739_485119E7 X-CRM114-Status: GOOD ( 29.05 ) 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 , Andrey Ryabinin , Andrew Morton , Dmitry Vyukov Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 2019-09-12 at 15:53 +0200, Vlastimil Babka wrote: > On 9/11/19 5:19 PM, Qian Cai wrote: > > > > The new config looks redundant and confusing. It looks to me more of a document update > > in Documentation/dev-tools/kasan.txt to educate developers to select PAGE_OWNER and > > DEBUG_PAGEALLOC if needed. > > > Agreed. But if you want it fully automatic, how about something > like this (on top of mmotm/next)? If you agree I'll add changelog > and send properly. > > ----8<---- > > From a528d14c71d7fdf5872ca8ab3bd1b5bad26670c9 Mon Sep 17 00:00:00 2001 > From: Vlastimil Babka > Date: Thu, 12 Sep 2019 15:51:23 +0200 > Subject: [PATCH] make KASAN enable page_owner with free stack capture > > --- > include/linux/page_owner.h | 1 + > lib/Kconfig.kasan | 4 ++++ > mm/Kconfig.debug | 5 +++++ > mm/page_alloc.c | 6 +++++- > mm/page_owner.c | 37 ++++++++++++++++++++++++------------- > 5 files changed, 39 insertions(+), 14 deletions(-) > > diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h > index 8679ccd722e8..6ffe8b81ba85 100644 > --- a/include/linux/page_owner.h > +++ b/include/linux/page_owner.h > @@ -6,6 +6,7 @@ > > #ifdef CONFIG_PAGE_OWNER > extern struct static_key_false page_owner_inited; > +extern bool page_owner_free_stack_disabled; > extern struct page_ext_operations page_owner_ops; > > 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 > Enables software tag-based KASAN mode. > This mode requires Top Byte Ignore support by the CPU and therefore I don't know how KASAN people will feel about this. Especially, KASAN_SW_TAGS was designed for people who complain about memory footprint of KASAN_GENERIC is too high as far as I can tell. I guess it depends on them to test the new memory footprint of KASAN to see if they are happy with it. > diff --git a/mm/Kconfig.debug b/mm/Kconfig.debug > index 327b3ebf23bf..a71d52636687 100644 > --- a/mm/Kconfig.debug > +++ b/mm/Kconfig.debug > @@ -13,6 +13,7 @@ config DEBUG_PAGEALLOC > depends on DEBUG_KERNEL > depends on !HIBERNATION || ARCH_SUPPORTS_DEBUG_PAGEALLOC && !PPC && !SPARC > select PAGE_POISONING if !ARCH_SUPPORTS_DEBUG_PAGEALLOC > + select PAGE_OWNER_FREE_STACK if PAGE_OWNER > ---help--- > Unmap pages from the kernel linear mapping after free_pages(). > Depending on runtime enablement, this results in a small or large > @@ -62,6 +63,10 @@ config PAGE_OWNER > > If unsure, say N. > > +config PAGE_OWNER_FREE_STACK > + def_bool n > + depends on PAGE_OWNER > + > config PAGE_POISONING > bool "Poison pages after freeing" > select PAGE_POISONING_NO_SANITY if HIBERNATION > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index c5d62f1c2851..d9e44671af3f 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -710,8 +710,12 @@ static int __init early_debug_pagealloc(char *buf) > if (kstrtobool(buf, &enable)) > return -EINVAL; > > - if (enable) > + if (enable) { > static_branch_enable(&_debug_pagealloc_enabled); > +#ifdef CONFIG_PAGE_OWNER > + page_owner_free_stack_disabled = false; > +#endif > + } > > return 0; > } > diff --git a/mm/page_owner.c b/mm/page_owner.c > index dee931184788..d4551d7012d0 100644 > --- a/mm/page_owner.c > +++ b/mm/page_owner.c > @@ -24,13 +24,15 @@ 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; > +bool page_owner_free_stack_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; > @@ -46,6 +48,11 @@ static int __init early_page_owner_param(char *buf) > if (strcmp(buf, "on") == 0) > page_owner_disabled = false; > > + if (IS_ENABLED(CONFIG_KASAN)) { > + page_owner_disabled = false; > + page_owner_free_stack_disabled = false; > + } > + > return 0; > } > early_param("page_owner", early_page_owner_param); > @@ -91,6 +98,8 @@ static void init_page_owner(void) > register_failure_stack(); > register_early_stack(); > static_branch_enable(&page_owner_inited); > + if (!page_owner_free_stack_disabled) > + static_branch_enable(&page_owner_free_stack); > init_early_allocated_pages(); > } > > @@ -148,11 +157,11 @@ 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 +170,8 @@ 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 +460,16 @@ 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 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel