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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 6AEB6C433ED for ; Tue, 18 May 2021 20:15:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4703C61154 for ; Tue, 18 May 2021 20:15:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231580AbhERUQg (ORCPT ); Tue, 18 May 2021 16:16:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49142 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230473AbhERUQf (ORCPT ); Tue, 18 May 2021 16:16:35 -0400 Received: from mail-lj1-x232.google.com (mail-lj1-x232.google.com [IPv6:2a00:1450:4864:20::232]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C2FA4C061573 for ; Tue, 18 May 2021 13:15:16 -0700 (PDT) Received: by mail-lj1-x232.google.com with SMTP id e11so12948273ljn.13 for ; Tue, 18 May 2021 13:15:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=xtjaCO4R8klBtYV4cZ2STfHktx3iSomuMheyVcZ48P8=; b=d39Pf7Mjb/VJ20jequHPFIXf1jxQ1Iplv/23httC+yl+k2BGcyqIfcCWTKhf4vqVus MuUBXQsC5N+frh0LJG06C14VUNUfPCnyN/EijbnrD/gVtFjv8G8PszKQP7cl88Npeqdz 9t6O7UJkRVKXxWvr1roegN5DnMGlo6qwtMaMd/fm0wgCdc3ZoECMcaXp9E3OwcB/EtML BzjDkOT1l3GUVFbWmUWqKem5zSFetbmFEfRdmvqKnh5YGLyAZ7YNqlb8jgKydCbDNuub 1UtBXBmAw6GlhoVK9uQQD5GJNVUSmrwBU8wCL5vtcI0JgtBy9vBL31jog5G3TbdraGcn DFFA== 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=xtjaCO4R8klBtYV4cZ2STfHktx3iSomuMheyVcZ48P8=; b=J3ffZuXEWZ7icUbvoWkdefsvCVlPVw2XMgd6SeFuU2ZscrcDHan2sXZ2PkQx9zsW4G ofhEXwbxWOCb+1WwaGY6Sdw/Pwfl/wQ7FH4ii5i0j12JVqJKMAuJZuxo2Tfwe2T5/9gp G9apHneilQENk7BExdO8zhw5VCRsYINRBXdbVMGEV7UPZ0z2lQiM06ceLw+reUkPq+R+ ZVTI4KNlIPhupZw3TG4Hg0lNMZYstZwtyTDX7b3lziealJWT+FwAl3e+5QboEbMcZyLV Z3s76mD4vxS9Zx4f/auP3ydHdtAAkYzkTpyjmyXjTZImQEsiYADj1nDB5p28W7t3xlQm X3MA== X-Gm-Message-State: AOAM530lbGzsNpe88vGv9Uh3oRURfDGObgk+3F9tWjeDoDDe8ZnG3KbX 8ShTyd+W88Pp+LfbIpERbHH2H2iXIVjAydErEeVk+Q== X-Google-Smtp-Source: ABdhPJwi+N/7kloDorfFQXbU071R6CcDMST5g4uJGXL2/Pu9sdY5iMWcur5lZ2t9dWDaPLFnzPfLpt9rckSrTUmv+DU= X-Received: by 2002:a2e:b6d2:: with SMTP id m18mr5100749ljo.233.1621368915089; Tue, 18 May 2021 13:15:15 -0700 (PDT) MIME-Version: 1.0 References: <20210518121447.GB7914@willie-the-truck> <20210518124311.r4fwv6lfz3erkqnb@treble> <20210518124819.lkzzgjcrh4cc5a6i@treble> <20210518200306.GE21560@worktop.programming.kicks-ass.net> In-Reply-To: <20210518200306.GE21560@worktop.programming.kicks-ass.net> From: Nick Desaulniers Date: Tue, 18 May 2021 13:15:04 -0700 Message-ID: Subject: Re: Linux Plumbers Conf 2021 To: Peter Zijlstra Cc: Josh Poimboeuf , Will Deacon , "Jose E. Marchesi" , "Paul E. McKenney" , Ard Biesheuvel , Catalin Marinas , Mark Rutland , linux-toolchains@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Tue, May 18, 2021 at 1:06 PM Peter Zijlstra wrote: > > On Tue, May 18, 2021 at 09:57:26AM -0700, Nick Desaulniers wrote: > > On Tue, May 18, 2021 at 6:23 AM Peter Zijlstra wrote: > > > > - validates noinstr annotation; *HOWEVER* we rely on objtool to NOP > > > all __sanitizer_cov_* calls in .noinstr/.entry text sections because > > > __no_sanitize_cov is 'broken' in all known compilers. > > > > ^ Do you have more information on this? > > Random link in the middle of a relevant thread: > > https://lkml.kernel.org/r/CANpmjNPNa2f=kAF6c199oYVJ0iSyirQRGxeOBLxa9PmakSXRbA@mail.gmail.com > > Notable quote: > > "It's everywhere. We cannot mark noinstr functions to not be > instrumented by KCOV/-fsanitize-coverage, because no compiler provides > an attribute to do so. GCC doesn't have > __attribute__((no_sanitize_coverage)) and Clang doesn't have > __attribute__((no_sanitize("coverage")), and therefore we can't have > __no_sanitize_coverage." Cool, thanks for the context. I was able to find this bug filed by Marco: https://bugs.llvm.org/show_bug.cgi?id=49035. I've cc'ed myself. We'll follow up on that. -- Thanks, ~Nick Desaulniers