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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F150C433FE for ; Thu, 20 Oct 2022 18:57:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230156AbiJTS5S (ORCPT ); Thu, 20 Oct 2022 14:57:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229832AbiJTS5Q (ORCPT ); Thu, 20 Oct 2022 14:57:16 -0400 Received: from mail-pf1-x42e.google.com (mail-pf1-x42e.google.com [IPv6:2607:f8b0:4864:20::42e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0898316A4DB for ; Thu, 20 Oct 2022 11:57:15 -0700 (PDT) Received: by mail-pf1-x42e.google.com with SMTP id g28so397054pfk.8 for ; Thu, 20 Oct 2022 11:57:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=ZFG8oe8zjIP3HtrEYf8FZ1cCVncWHGDhPegdRUm6pSk=; b=JH10v71f9cO/zrGHhWXMzQx4+lZEXvmFPiD6f82j66NBiYRArMO6WA87v5WRzOFdmJ vFAhDRdieYSaEwIMaX4NLT7dRZsmxrRodnE3B2inGJhsPNES+Wrq+P3EMm9m7qfLm7+X VDQRrM3G4guBVWiBNXcjYnt5uMWuXxdXqgHv8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=ZFG8oe8zjIP3HtrEYf8FZ1cCVncWHGDhPegdRUm6pSk=; b=2p8/mWiJeNXojWD5XF9p/NOcMCv4Z9HvoKLKHN5S7R57Pagp1YpVd6Lly8TfySU3bj KftHRIfxHu628re/8zXwRDxNxadNCpgDBoS4IKHoYh+2Tmk5UCSfJEcNelnftDcKjSpM 5wrazwvuuaushKO9xkY9VY5ONBVaUWuvjTlO7Fq74r6F7qzGIgvsH3jh+IhczcDvViZg V1PZmy5Ohf12ZcPwkhNpRFRX4zf6kojfzR1I/sBSEtBUYBoJun1Eu59+js0LP87LzkZE KW0pA4yLYJX1bQqzX3YbyP+yEt71Iq3a1iOedbW+84EquRr06ZoGBJxIHkAOf3/ivZMe wRzQ== X-Gm-Message-State: ACrzQf1Ycpcg/jkgAFGx3dDLSRODbbbL2tidFXR++J4Dl+ep6tTytksx ewBQZTuu7ome8I9IlzcZ08RzwQ== X-Google-Smtp-Source: AMsMyM5LsHsFEMX8I6dkcpYhAJP8fLYRo6gtf8HpJpwWxcUentkixVPXvC3hRVRGYAOeDT0aPDAVFw== X-Received: by 2002:a05:6a00:1707:b0:563:235:769b with SMTP id h7-20020a056a00170700b005630235769bmr15374927pfc.19.1666292234509; Thu, 20 Oct 2022 11:57:14 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id c28-20020aa7953c000000b0053725e331a1sm13669135pfp.82.2022.10.20.11.57.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Oct 2022 11:57:13 -0700 (PDT) Date: Thu, 20 Oct 2022 11:57:12 -0700 From: Kees Cook To: Linus Torvalds Cc: "Jason A. Donenfeld" , Alexey Dobriyan , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, mm-commits@vger.kernel.org, masahiroy@kernel.org, gregkh@linuxfoundation.org, andriy.shevchenko@linux.intel.com, Stephen Rothwell Subject: Re: [PATCH -mm] -funsigned-char, x86: make struct p4_event_bind::cntr signed array Message-ID: <202210201151.ECC19BC97A@keescook> References: <20221020000356.177CDC433C1@smtp.kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 20, 2022 at 10:42:25AM -0700, Linus Torvalds wrote: > On Thu, Oct 20, 2022 at 10:33 AM Jason A. Donenfeld wrote: > > > > Or sometimes with objdump, I've had more success by keeping debug > > symbols, and then trimming offsets from jmps. > > objdump is what I'm using, and it actually seems ok on individual object files. > > Now I just need to script the "do all the object files" and see how > massive the end result is. For the a/b build, I start with all*config, then: # Stop painful noise CONFIG_KCOV=n CONFIG_GCOV_KERNEL=n CONFIG_GCC_PLUGINS=n CONFIG_IKHEADERS=n CONFIG_KASAN=n CONFIG_UBSAN=n CONFIG_KCSAN=n CONFIG_KMSAN=n # Get us source/line details CONFIG_DEBUG_KERNEL=y CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y CONFIG_DEBUG_INFO_REDUCED=n CONFIG_DEBUG_INFO_COMPRESSED=n CONFIG_DEBUG_INFO_SPLIT=n And to keep other build-time junk stabilized[1], I build with these make options: KBUILD_BUILD_TIMESTAMP=1970-01-01 KBUILD_BUILD_USER=user KBUILD_BUILD_HOST=host KBUILD_BUILD_VERSION=1 For the code diff, I use: objdump --disassemble --demangle --no-show-raw-insn --no-addresses and when doing the manual examination: objdump --disassemble --demangle --reloc --source -l --no-show-raw-insn My not-great way to filter out the movsbl/movzbl, I added this to diff: -I '\bmov[sz]bl\b' -- Kees Cook