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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 B0E93C433E0 for ; Mon, 15 Jun 2020 14:55:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8E47020644 for ; Mon, 15 Jun 2020 14:55:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ecmGxFrs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730832AbgFOOzS (ORCPT ); Mon, 15 Jun 2020 10:55:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730405AbgFOOzR (ORCPT ); Mon, 15 Jun 2020 10:55:17 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0625C061A0E for ; Mon, 15 Jun 2020 07:55:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=4zGfMuE5j27OryPVO0IL9HdYeTzioBh7k+J5vYWJu6A=; b=ecmGxFrsTbQdidZbBn8r7gMJyz 3u0f1y1KUxKvAma9auXgAZX1uvUJnS0uswNfPi29xpk5AUCYchyuSTZg4Qo8RlNnr9IobCk9DphEp BQCVVpHX+K3JTBDfCopaBFY3rMuk5iuD2K12uvvaf934nZA6T3arFASL1lbKi0cIYbzw+8zwcGre8 F6cFbJIYZ5yDZM6aRjwtozFn7JPGVG+/z6OUEip4dJsYKn3P4UVtBVQxPf0W43+po4zRU75CVudhL mS8GfZvmHf7nJzyh0iZ65A6niEvPJVkFSrXxfOVrazmCVOHesHBwjbbwJxlfT/bSs1+9O7ixM1hxS wQtnf8Vw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkqVe-00072A-5A; Mon, 15 Jun 2020 14:54:50 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id C3DD930604B; Mon, 15 Jun 2020 16:54:48 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id AFEF8203B8070; Mon, 15 Jun 2020 16:54:48 +0200 (CEST) Date: Mon, 15 Jun 2020 16:54:48 +0200 From: Peter Zijlstra To: Marco Elver Cc: Dmitry Vyukov , Andrey Konovalov , Mark Rutland , Borislav Petkov , Thomas Gleixner , Ingo Molnar , clang-built-linux , "Paul E. McKenney" , Alexander Potapenko , kasan-dev , LKML , the arch/x86 maintainers , Andrew Morton , Josh Poimboeuf Subject: Re: [PATCH -tip v3 1/2] kcov: Make runtime functions noinstr-compatible Message-ID: <20200615145448.GV2531@hirez.programming.kicks-ass.net> References: <20200608110108.GB2497@hirez.programming.kicks-ass.net> <20200611215538.GE4496@worktop.programming.kicks-ass.net> <20200612114900.GA187027@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 15, 2020 at 09:53:06AM +0200, Marco Elver wrote: > For KCSAN the crash still happens in check_preemption_disabled, in the > inlined native_save_fl function (apparently on its 'pushf'). If I turn > fixup_bad_iret's __this_cpu_read into a raw_cpu_read (to bypass > check_preemption_disabled), no more crash with KCSAN. Yeah, I can't see anything weird there with KCSAN + KCOV + NOP :-(