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 04BD6C433EF for ; Thu, 14 Jul 2022 09:20:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238158AbiGNJUx (ORCPT ); Thu, 14 Jul 2022 05:20:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238063AbiGNJUh (ORCPT ); Thu, 14 Jul 2022 05:20:37 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 44F6B545CE for ; Thu, 14 Jul 2022 02:17:35 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8A24AB823EF for ; Thu, 14 Jul 2022 09:17:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 989A0C34114; Thu, 14 Jul 2022 09:17:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657790251; bh=AqWLm0A0re9k6XzaqKJt9/6aUdpL6f/earpvIab68qU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qIxFF/bQB36iQeO6AyHEvJdN76oyyAT4Gm/QabEwk8woXG8WjzaBDYgeKmVngMbgy aFi3pu0kV3veSaCjUGeoqUD2j9+Qgg21+v6O9Ao5h18qUs0b4/uEC0mnpNzZDeeRzK Z2xFGBpVpD9ueK2LpE6JI4lM4F4haqK1DFoJw1cI= Date: Thu, 14 Jul 2022 11:17:28 +0200 From: Greg Kroah-Hartman To: Josh Poimboeuf Cc: Ben Hutchings , kernel test robot , Josh Poimboeuf , "Steven Rostedt (VMware)" , kbuild-all@lists.01.org, linux-kernel@vger.kernel.org Subject: Re: [linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction Message-ID: References: <202207130344.dwXyDmTk-lkp@intel.com> <7b7c5908ccb62f365fff8f55d32baae4c4a6ea89.camel@kernel.org> <20220714001842.drzq7oeyk4akk2xo@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220714001842.drzq7oeyk4akk2xo@treble> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 13, 2022 at 05:18:42PM -0700, Josh Poimboeuf wrote: > On Thu, Jul 14, 2022 at 01:41:58AM +0200, Ben Hutchings wrote: > > On Wed, 2022-07-13 at 03:57 +0800, kernel test robot wrote: > > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y > > > head: ba398a0e54049bb6a1c102245ae84103f103ff2c > > > commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls > > > config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@intel.com/config) > > > compiler: gcc-11 (Debian 11.3.0-3) 11.3.0 > > > reproduce (this is a W=1 build): > > > # https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a > > > git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git > > > git fetch --no-tags linux-stable-rc linux-5.10.y > > > git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a > > > # save the config file > > > mkdir build_dir && cp config build_dir/.config > > > make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/ > > > > > > If you fix the issue, kindly add following tag where applicable > > > Reported-by: kernel test robot > > > > > > All warnings (new ones prefixed by >>): > > > > > > > > arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction > > > > > > > > > objdump-func vmlinux.o ftrace_epilogue: > > > 0000 000000000008ca70 : > > > 0000 8ca70: e9 00 00 00 00 jmp 8ca75 8ca71: R_X86_64_PLT32 ftrace_stub-0x4 > > > 0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1) > > > > > > > I don't know what's going on here. There's a jump to a ret (now > > potentialy a rethunk), and nothing obviously unreachable. > > ftrace_epilogue got simplified by commit 0c0593b45c9b "x86/ftrace: Make > > function graph use ftrace directly" which maybe avoids the warning in > > the mainline. > > The unreachable warning is actually pointing to ftrace_stub(). I think > you need > > 18660698a3d3 ("x86/ftrace: Add UNWIND_HINT_FUNC annotation for ftrace_stub") Thanks for the hint, now queued up! greg k-h