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 29402C54EBC for ; Thu, 12 Jan 2023 16:19:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229524AbjALQT2 (ORCPT ); Thu, 12 Jan 2023 11:19:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53194 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230263AbjALQSA (ORCPT ); Thu, 12 Jan 2023 11:18:00 -0500 Received: from mail.skyhub.de (mail.skyhub.de [5.9.137.197]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8AD9DD4E; Thu, 12 Jan 2023 08:14:58 -0800 (PST) Received: from zn.tnic (p5de8e9fe.dip0.t-ipconnect.de [93.232.233.254]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 1AE8F1EC04F0; Thu, 12 Jan 2023 17:14:57 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1673540097; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=kXgGOS0t1Dmzod2SUlVqdk8NheeeK7L+8V9FBwGiZ2c=; b=m3JMpkzRjC8s+Ax3AVMnGYV4D08mDT/nAPRGVvPn9MS6OIJBqz47llq3S/Zr//hgi7Lujd RfYRnQupWB15RFD0Ey1QDe50Yidqw1+88F0QbkzxSoFaZpIW7gSVU8GDD+LIHhxRpbC2uN +Peu+rXB3xj9M6aLYIr4P12WzeD3V5I= Date: Thu, 12 Jan 2023 17:14:52 +0100 From: Borislav Petkov To: Miguel Ojeda Cc: kernel test robot , llvm@lists.linux.dev, oe-kbuild-all@lists.linux.dev, rust-for-linux@vger.kernel.org, lkml , Yujie Liu Subject: Re: [bp:tip-x86-alternatives 1/1] error[E0588]: packed type cannot transitively contain a `#[repr(align)]` type Message-ID: References: <202212272003.rgQDX8DQ-lkp@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: rust-for-linux@vger.kernel.org On Sat, Jan 07, 2023 at 01:38:42AM +0100, Miguel Ojeda wrote: > You are of course right that the instructions are not complete, I just > meant to add a bit of context, i.e. that Rust got enabled due to the > config, but as far as I understand, it shouldn't be getting enabled in > the other ones for the moment. Right, or at least the repro instructions should state it clear. Btw, this is part of a long-running feedback process we're giving to the 0day bot in order to make their reports as user friendly as possible. > My point was that the script expects some variables set by `Makefile`, > similar to `$CC` etc., so that output does not imply you have (or not) > a suitable Rust toolchain installed (i.e. it will currently also fail > if you have it installed). Aha. > Meanwhile (of course it is not the same as proper reproduction > instructions since the LKP team may do something different), the > documentation on how to set it up for a normal developer is at: > https://www.kernel.org/doc/html/latest/rust/quick-start.html, in case > it helps (if you are up for it... :) Probably that link should be part of those reproduction instructions. > > And while we're reporting bugs: the error message from the compiler itself could > > use some "humanization" - I have zero clue what it is trying to tell me. > > What would you want to see? We can ask the relevant Rust team to see > if they can improve it. > > In general, note that you can ask `rustc` to further explain an error > giving it the code with `--explain`. The compiler suggests this > itself, but sadly the robot cut it out :( Well, I find having an --explain option too much. But there are perhaps reasons for it. One improvement could be, IMHO, they could turn on --explain automatically when it results in a build error. So that you don't have to do it yourself. What would be better, tho, is if there were no --explain option at all and the warnings are as human readable as possible. > For more information about this error, try `rustc --explain E0588` > > In this case, it gives: > > A type with `packed` representation hint has a field with `align` > representation hint. > ... so the struct is: struct alt_instr { s32 instr_offset; /* original instruction */ s32 repl_offset; /* offset to replacement instruction */ union { struct { u32 cpuid: 16; /* CPUID bit set for replacement */ u32 flags: 16; /* patching control flags */ }; u32 ft_flags; }; u8 instrlen; /* length of original instruction */ u8 replacementlen; /* length of new instruction */ } __packed; and everything is naturally aligned. So I'm guessing this is a rust bindings glue shortcoming or so... Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette