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=-10.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 F285EC282DD for ; Thu, 23 May 2019 01:47:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A67232081C for ; Thu, 23 May 2019 01:47:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RAHsstRp" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728994AbfEWBrh (ORCPT ); Wed, 22 May 2019 21:47:37 -0400 Received: from mail-ed1-f67.google.com ([209.85.208.67]:40605 "EHLO mail-ed1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727305AbfEWBrh (ORCPT ); Wed, 22 May 2019 21:47:37 -0400 Received: by mail-ed1-f67.google.com with SMTP id j12so6656051eds.7 for ; Wed, 22 May 2019 18:47:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=GhDOpD+a8hZjtMNIICSVb0siagk1dgNYZl1xyc8Nh/s=; b=RAHsstRpbLf3k0oQL3ZdAxZNnhWB9ZQx211cpf9TbvlO+3D6SP3+7mmzu0LlgM8ldM YwAGFs03guyR/13fWGrGfOdZTr/4PaK0iMdmiCPXcSlfRGUqpo8DxXbX92/urJpReydV ZjMcA3YzivAX4MdtizE4zM2cqlAYzaJ6ofb2Iz/tCiBMhFHhoO1Ln/GsI0hd8uSESLm5 ekrjS6LIpq+TSnewT23Yp7Fd825pMCcCj10h04CJZEpHj9FPgUqM+w5N50Bq50LoFzva QPaI8Irw+hkLdwcEis8BoraD6dx5NA7m5xWV/KpTMQpf0oBfAknVCAYX1XMfmXp0SvHg gpUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=GhDOpD+a8hZjtMNIICSVb0siagk1dgNYZl1xyc8Nh/s=; b=NVOmBdOftoW2yx0pvba/JiO3xlflkRYuH6HpqvzC94Hvi/7bZT8E1cxkAk2ErteS2J 23DBvlAnUB96gdWHKU4xaCK9xYWgRjjWLEXK9n2mt7ROnI2brLV2Q3q+NXDKR8hbL5LG muPSsaq4J9jSpFw9P1V/fyqUg1KLhG/IICACvk9pS2OjUwhQys6G2bYtv6ozsd4lEgWQ cXGouumsIlBq/BkukCPOJlA1tjAyFsbdcYwObLZNV1Of5ouKS8zjHAhI0/4t8ln56tMg KMDf11QH35TVWb5t66tL+Q3JzlN4uq5QaRMDP0qFdtnuboD0H9gpG7epx+g2wNg6sA6Q DwMQ== X-Gm-Message-State: APjAAAXi76DHxcZSGS5JkFZVqlxw1nA/E/IMtbuSEg0s5fi6E7IGwmM0 JVhSHT6sedh4Pbn6ioKb0k4= X-Google-Smtp-Source: APXvYqw/Jq1ILra5N4580sMe/IeEHxM9pGabgCBEXURpJwUD5K34xnviPekD1/bHpG4yUCsySFosJA== X-Received: by 2002:a17:906:488e:: with SMTP id v14mr33945656ejq.216.1558576055392; Wed, 22 May 2019 18:47:35 -0700 (PDT) Received: from archlinux-epyc ([2a01:4f9:2b:2b15::2]) by smtp.gmail.com with ESMTPSA id x22sm7584539edd.59.2019.05.22.18.47.34 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 22 May 2019 18:47:34 -0700 (PDT) Date: Wed, 22 May 2019 18:47:32 -0700 From: Nathan Chancellor To: Andrey Konovalov Cc: Andrey Ryabinin , Alexander Potapenko , Dmitry Vyukov , kasan-dev , Linux Memory Management List , LKML , Nick Desaulniers , clang-built-linux@googlegroups.com Subject: Re: [PATCH v2] kasan: Initialize tag to 0xff in __kasan_kmalloc Message-ID: <20190523014732.GA17640@archlinux-epyc> References: <20190502153538.2326-1-natechancellor@gmail.com> <20190502163057.6603-1-natechancellor@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.4 (2019-03-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 02, 2019 at 06:40:52PM +0200, Andrey Konovalov wrote: > On Thu, May 2, 2019 at 6:31 PM Nathan Chancellor > wrote: > > > > When building with -Wuninitialized and CONFIG_KASAN_SW_TAGS unset, Clang > > warns: > > > > mm/kasan/common.c:484:40: warning: variable 'tag' is uninitialized when > > used here [-Wuninitialized] > > kasan_unpoison_shadow(set_tag(object, tag), size); > > ^~~ > > > > set_tag ignores tag in this configuration but clang doesn't realize it > > at this point in its pipeline, as it points to arch_kasan_set_tag as > > being the point where it is used, which will later be expanded to > > (void *)(object) without a use of tag. Initialize tag to 0xff, as it > > removes this warning and doesn't change the meaning of the code. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/465 > > Signed-off-by: Nathan Chancellor > > Reviewed-by: Andrey Konovalov > > Thanks! > Thanks Andrey! Did anyone else have any other comments or can this be picked up? Cheers, Nathan