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 E0B46C4332E for ; Fri, 20 Mar 2020 08:26:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAB0220767 for ; Fri, 20 Mar 2020 08:26:20 +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="pUzm+5eU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbgCTI0T (ORCPT ); Fri, 20 Mar 2020 04:26:19 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:52524 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726232AbgCTI0T (ORCPT ); Fri, 20 Mar 2020 04:26:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=RAiCDcH77jHDXYkeTD8SKPLyPkTVQvNLw8kPgs7l5xU=; b=pUzm+5eUP3tPVNOkrWaFIeBxRc yRcTLahi18JHzsFCG6HFwFLz0Do+6lzpyphE8AszSbKwXFoUEgFrGwEx42r8QazBKt4v0nzF4e/KE Ybkd/YoygJOTf+ovXA8ew0amG51k21gWYNi2V615IE1hEeEvrfJ3Uz1W5ceti7ea6JiWFRq2wmJPh Yq4zZpyCdMfJDPc9wMdrZ4FmxIy7Xw/BriaARsAc42/DDtHmsNAiGrfPWduspu5o0NxYB3C1SCqUW jl2J526fddPFI3U6poBL3EueBCU72Uv/ZF7ZH3b6rDEDjsnZLzx2ZxkPmReA7OzsBC3GOLFFT61Wm d4SBC+Qw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFCyu-0008KV-9t; Fri, 20 Mar 2020 08:26:16 +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 CFE08300235; Fri, 20 Mar 2020 09:26:13 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8F16E286B1726; Fri, 20 Mar 2020 09:26:13 +0100 (CET) Date: Fri, 20 Mar 2020 09:26:13 +0100 From: Peter Zijlstra To: Josh Poimboeuf Cc: Randy Dunlap , Stephen Rothwell , Linux Next Mailing List , Linux Kernel Mailing List , Kees Cook Subject: Re: linux-next: Tree for Mar 18 (objtool) Message-ID: <20200320082613.GA20696@hirez.programming.kicks-ass.net> References: <20200318220920.48df2e76@canb.auug.org.au> <20200318182352.2dgwwl4ugbwndi4x@treble> <20200318200542.GK20730@hirez.programming.kicks-ass.net> <20200319173101.wufpymi7obhqgoqd@treble> <20200319173326.oj4qs24x4ly5lrgt@treble> <20200319174028.azzaisoj5gbss7zk@treble> <20200319174550.4wpx4j357nw67nzz@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200319174550.4wpx4j357nw67nzz@treble> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 19, 2020 at 12:45:50PM -0500, Josh Poimboeuf wrote: > > On Thu, Mar 19, 2020 at 12:33:31PM -0500, Josh Poimboeuf wrote: > > > Actually I suspect it's the __builtin_unreachable() annotation which is > > > making UBSAN add the __builtin_trap()... because I don't see any double > > > UD2s for WARNs. > Actually, removing __builtin_unreachable() *does* make the extra UD2 go > away -- I forgot I had some silly debug code. LOL, check this: "Built-in Function: void __builtin_unreachable (void) If control flow reaches the point of the __builtin_unreachable, the program is undefined. It is useful in situations where the compiler cannot deduce the unreachability of the code. " Which, I bet, is what makes UBSAN insert that __builtin_trap(). What a friggin mess :/