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=-2.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 0DFACC11F69 for ; Thu, 1 Jul 2021 13:31:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD71261350 for ; Thu, 1 Jul 2021 13:31:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231940AbhGANeZ (ORCPT ); Thu, 1 Jul 2021 09:34:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48522 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbhGANeZ (ORCPT ); Thu, 1 Jul 2021 09:34:25 -0400 Received: from mail-ej1-x629.google.com (mail-ej1-x629.google.com [IPv6:2a00:1450:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 97A72C061762 for ; Thu, 1 Jul 2021 06:31:54 -0700 (PDT) Received: by mail-ej1-x629.google.com with SMTP id bg14so10396682ejb.9 for ; Thu, 01 Jul 2021 06:31:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=F9xHPQXfeX85p/WzrKNX5asqql2B/nD64WETM/hhNus=; b=rPkrb7S1fk4T3qkJ10Ep2j4MR6kgQaC6BsJseApFIwDMzhwuu3VfF4W+PMn+D6OOsj leSkEpTvERGV5xLo8VbBUsUr6mDM5rt1doaDh50MTc0uzsUlN3zRbh2OYSSAHBJiN6li bdQWhTsymoM6+mvoXx3OTtT4O61r1hWcjpzftezV2yOqO0RfmEfAX5YUEsKJs5htq92G PAQJrU/eJlCnP6y154lnlyQfgEYTmc87dxS+SyvZO3Cl9jM1WBBTv2ljPQLxX5FHDlcc pCiiqVPZIQkb+xQuzE49/flY/F7wWvZhXhUebyqm5a0zD+rEBDd72pM6O3vUDjN392Wt D2fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=F9xHPQXfeX85p/WzrKNX5asqql2B/nD64WETM/hhNus=; b=UE9UKUtWFPOmS006DknTH6+zxgZK3dls0yLxQT1/6cNThic4I/VwEYOV75N1OGq22v tk/almGqRU59WIOPT2kHbi1eXbERvyhfUsczkOJeU9r18CEhgtpi5Ex9rB9dWS5XNktb XR3g2Eg0T/uD8tIJKvjG9XURuEjCAKxKGp6MRh+crQ1E8etUgDwVqT4rFbbdrS8g/uws 8G9xjt949B8KsV3HTgeSsgoxiawUbz6HnsjY1ojQ/lvzAm9pC32oxFXlyodHDAPgue5Q XnSotUzqeInAlw9anw4lvfxGOeRhinwApPkp2IBTV1wj6iR02zFlHjAZQiM1HoltJ9vW 8i2g== X-Gm-Message-State: AOAM533nSsdBSBYgftNVahUlYDIzKpczmiZeY6j+EFvK6bgUsKS1LYDK tuBuyhc/ComIMmoWv1Fn2oxjR35fwxDVg4/IV1U= X-Google-Smtp-Source: ABdhPJwAB9zNDvwIwLlvuGpl2XmkQHgjogSwTqCGj4FJ6uy6ez3lXb60hBmJa9obZ737ErpszWY/M6A6HyDbpv+9BfA= X-Received: by 2002:a17:907:9f0:: with SMTP id ce16mr42484016ejc.126.1625146312962; Thu, 01 Jul 2021 06:31:52 -0700 (PDT) MIME-Version: 1.0 References: <20210630134943.20781-1-yee.lee@mediatek.com> <20210630134943.20781-2-yee.lee@mediatek.com> In-Reply-To: From: Andrey Konovalov Date: Thu, 1 Jul 2021 16:31:42 +0300 Message-ID: Subject: Re: [PATCH v3 1/1] kasan: Add memzero init for unaligned size under SLUB debug To: Marco Elver , yee.lee@mediatek.com Cc: wsd_upstream@mediatek.com, Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , Andrew Morton , Matthias Brugger , "open list:KASAN" , "open list:MEMORY MANAGEMENT" , open list , "moderated list:ARM/Mediatek SoC support" , "moderated list:ARM/Mediatek SoC support" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 30, 2021 at 10:13 PM Marco Elver wrote: > > > + if (IS_ENABLED(CONFIG_SLUB_DEBUG) && init && ((unsigned long)size & KASAN_GRANULE_MASK)) { > > + init = false; > > + memzero_explicit((void *)addr, size); > > + } > > size = round_up(size, KASAN_GRANULE_SIZE); > > > > hw_set_mem_tag_range((void *)addr, size, tag, init); > > I think this solution might be fine for now, as I don't see an easy way > to do this without some major refactor to use kmem_cache_debug_flags(). > > However, I think there's an intermediate solution where we only check > the static-key 'slub_debug_enabled' though. Because I've checked, and > various major distros _do_ enabled CONFIG_SLUB_DEBUG. But the static > branch just makes sure there's no performance overhead. > > Checking the static branch requires including mm/slab.h into > mm/kasan/kasan.h, which we currently don't do and perhaps wanted to > avoid. Although I don't see a reason there, because there's no circular > dependency even if we did. Most likely this won't be a problem. We already include ../slab.h into many mm/kasan/*.c files. > Andrey, any opinion? I like this approach. Easy to implement and is better than checking only CONFIG_SLUB_DEBUG. Thanks, Marco!