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 4ACF5C7EE2F for ; Tue, 6 Jun 2023 21:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239590AbjFFVwT (ORCPT ); Tue, 6 Jun 2023 17:52:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233934AbjFFVwQ (ORCPT ); Tue, 6 Jun 2023 17:52:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8DE011706; Tue, 6 Jun 2023 14:52:15 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 28037630B4; Tue, 6 Jun 2023 21:52:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0A546C433EF; Tue, 6 Jun 2023 21:52:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1686088334; bh=GPZrA31f5hxmdBQeDG6A06kCs0MvEaCMExub/aQHK6o=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MZA8aQNRXPiXYuBKwCVGW8FspS/pRcnw0s21K+rBM+pQQrH9uaJHokeMwT98oSe9n Sq44RUv8bYHWcezzQ2QumXVs3DmyRVLfG+2zOj3UdDmXq6qER6rMo58Xtk6446KUSc pBwUPw0zhvd9W2/FCzJeJ7PEhC1NvscSX/6denbN53plER72iz9edm9h3sGjbKMIW3 /tgtnHUiqNsShmJ9OGeG20u4pRTsTklBAwbdfZuG2UWBcKMiACmYgdan1hTJ8dWbyb cbpZSagvBGEbvQUGU/ShMNFQNjC98HaWUXlJeSw2dkFUEAiYvUpAtzta7bBjoKcg3Q MLsYbjb/8BMMw== Date: Tue, 6 Jun 2023 14:52:12 -0700 From: Josh Poimboeuf To: Miguel Ojeda , Wedson Almeida Filho Cc: llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, x86@kernel.org, Miroslav Benes , kernel test robot , Peter Zijlstra , Alex Gaynor , rust-for-linux@vger.kernel.org Subject: Re: [tip:objtool/core 8/12] vmlinux.o: warning: objtool: rust_begin_unwind+0x5c: rust_helper_BUG() is missing a __noreturn annotation Message-ID: <20230606215212.r7if2gsynajugf6j@treble> References: <202306070408.EFxuDoRs-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <202306070408.EFxuDoRs-lkp@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Miguel, Wedson, Objtool detected that rust_helper_BUG() doesn't return, and seems to be missing a __noreturn. But it actually *does* have __noreturn. The problem is actually that its rust callees don't seem to know that, i.e. they assume it returns. After a little digging I found this comment in rust panic(): unsafe { bindings::BUG() }; // Bindgen currently does not recognize `__noreturn` so `BUG` returns `()` // instead of `!`. See . loop {} So it seems to be an issue with bindgen, though that github issue has been resolved. Any idea when this will show up in a toolchain? In the meantime we may have to get objtool to manually silence the warning, unless you have any better ideas. On Wed, Jun 07, 2023 at 04:57:42AM +0800, kernel test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git objtool/core > head: ff9a6459bbec06df7da2545020d7383aba13b3fb > commit: fedb724c3db5490234ddde0103811c28c2fedae0 [8/12] objtool: Detect missing __noreturn annotations > config: x86_64-randconfig-a012-20230606 (https://download.01.org/0day-ci/archive/20230607/202306070408.EFxuDoRs-lkp@intel.com/config) > compiler: clang version 15.0.7 (https://github.com/llvm/llvm-project.git 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a) > reproduce (this is a W=1 build): > mkdir -p ~/bin > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=fedb724c3db5490234ddde0103811c28c2fedae0 > git remote add tip https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git > git fetch --no-tags tip objtool/core > git checkout fedb724c3db5490234ddde0103811c28c2fedae0 > # save the config file > mkdir build_dir && cp config build_dir/.config > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash > > If you fix the issue, kindly add following tag where applicable > | Reported-by: kernel test robot > | Closes: https://lore.kernel.org/oe-kbuild-all/202306070408.EFxuDoRs-lkp@intel.com/ > > All warnings (new ones prefixed by >>): > > >> vmlinux.o: warning: objtool: rust_begin_unwind+0x5c: rust_helper_BUG() is missing a __noreturn annotation > > > objdump-func vmlinux.o rust_begin_unwind: > 0000 00000000000b9e69 : > 0000 b9e69: 48 83 ec 48 sub $0x48,%rsp > 0004 b9e6d: 48 89 e0 mov %rsp,%rax > 0007 b9e70: 48 89 38 mov %rdi,(%rax) > 000a b9e73: 48 8d 4c 24 08 lea 0x8(%rsp),%rcx > 000f b9e78: 48 89 01 mov %rax,(%rcx) > 0012 b9e7b: 48 c7 41 08 00 00 00 00 movq $0x0,0x8(%rcx) b9e7f: R_X86_64_32S _RNvXsR_NtCs3yuwAp0waWO_4core3fmtRNtNtNtB7_5panic10panic_info9PanicInfoNtB5_7Display3fmtCsfATHBUcknU9_6kernel > 001a b9e83: 48 8d 54 24 18 lea 0x18(%rsp),%rdx > 001f b9e88: 48 c7 02 00 00 00 00 movq $0x0,(%rdx) b9e8b: R_X86_64_32S .rodata+0x137d8 > 0026 b9e8f: 48 c7 42 08 02 00 00 00 movq $0x2,0x8(%rdx) > 002e b9e97: 48 c7 42 10 00 00 00 00 movq $0x0,0x10(%rdx) > 0036 b9e9f: 48 89 4a 20 mov %rcx,0x20(%rdx) > 003a b9ea3: 48 c7 42 28 01 00 00 00 movq $0x1,0x28(%rdx) > 0042 b9eab: 48 c7 c7 00 00 00 00 mov $0x0,%rdi b9eae: R_X86_64_32S _RNvNtNtCsfATHBUcknU9_6kernel5print14format_strings5EMERG > 0049 b9eb2: 48 c7 c6 00 00 00 00 mov $0x0,%rsi b9eb5: R_X86_64_32S .rodata+0x13568 > 0050 b9eb9: 31 c0 xor %eax,%eax > 0052 b9ebb: e8 00 00 00 00 call b9ec0 b9ebc: R_X86_64_PLT32 _printk-0x4 > 0057 b9ec0: e8 00 00 00 00 call b9ec5 b9ec1: R_X86_64_PLT32 rust_helper_BUG-0x4 > 005c b9ec5: eb fe jmp b9ec5 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki -- Josh