From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751860AbdB1BY2 (ORCPT ); Mon, 27 Feb 2017 20:24:28 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:39026 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751485AbdB1BYZ (ORCPT ); Mon, 27 Feb 2017 20:24:25 -0500 Date: Mon, 27 Feb 2017 15:23:28 -0800 From: Guenter Roeck To: Josh Poimboeuf Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: Crash in -next due to 'objtool: Improve detection of BUG() and other dead ends' Message-ID: <20170227232328.GA1604@roeck-us.net> References: <20170227205923.GA6466@roeck-us.net> <20170227222114.p6vdugfmfjfprt47@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170227222114.p6vdugfmfjfprt47@treble> User-Agent: Mutt/1.5.24 (2015-08-30) X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Josh, On Mon, Feb 27, 2017 at 04:21:14PM -0600, Josh Poimboeuf wrote: > On Mon, Feb 27, 2017 at 12:59:23PM -0800, Guenter Roeck wrote: > > Hi, > > > > my qemu tests for mips64 in -next fail as follows. > > > > ... > > VFS: Mounted root (ext3 filesystem) on device 8:0. > > Freeing unused kernel memory: 304K > > This architecture does not have kernel memory protection. > > Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000a > > > > ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000a > > > > There is no symbol traceback, and I don't see any other (obvious) error > > message. bisect points to commit 'objtool: Improve detection of BUG() > > and other dead ends'; reverting that patch fixes the problem. > > Bisect log is attached below. > > > > The script used to run the test as well as the root file system is available > > at https://github.com/groeck/linux-build-test/tree/master/rootfs/mips64 > > > > A complete log is available at > > http://kerneltests.org/builders/qemu-mips64-next/builds/592/steps/qemubuildcommand/logs/stdio > > Hi Guenter, > > This failure doesn't make much sense. Objtool (and the reported bad > patch) are x86-only and should have nothing to do with mips64. Would it > be possible for you to double check the error? > I already did; after all, bisect points to the patch, and reverting it fixes the problem. After looking into the patch, I concluded that the following might help. -#define unreachable() annotate_unreachable(); __builtin_unreachable() +#define unreachable() do { annotate_unreachable(); __builtin_unreachable(); } while (0) and it does ... > Otherwise I could try to recreate. Do you have a recommendation for a > mips cross-compiler? (preferably something that's already built and that > might work on Fedora) > I use gcc 4.9.0 from https://www.kernel.org/pub/tools/crosstool/files/bin/x86_64/4.9.0/ Guenter