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 0071FC433FE for ; Mon, 17 Oct 2022 12:24:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229808AbiJQMYF (ORCPT ); Mon, 17 Oct 2022 08:24:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51708 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229940AbiJQMXy (ORCPT ); Mon, 17 Oct 2022 08:23:54 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D869A12755 for ; Mon, 17 Oct 2022 05:23:37 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 264CA218B0; Mon, 17 Oct 2022 12:23:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1666009415; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ch0lcDKHBLmzGMbIyCzPneAQ4BwpLTCHPCHZaVD3tlg=; b=bGRcT684pGX3Ue4tFZ9X1+UduV3q5Gf2kV+yfUg7i/Ep8cNuNr30XOn4CQHAx5bDcPRI7l qUtQAn2hN1vNeDqZO92eaGE/2rNjJCsDnVR6JKY9f4HFfwec7X8R6sMUUID7mqeukkjPGt OuM4LPXtTFa2a5tVAzwyuSeSqyTfqx0= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1666009415; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ch0lcDKHBLmzGMbIyCzPneAQ4BwpLTCHPCHZaVD3tlg=; b=ZSfKP3QaOFzVuK52JDLVOx6/ZwqH6uzKlytPp/izWrzNAuqjuC0fImhNL4wPh2z1ydONGI t82yvTq0rAfS9CBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F180613398; Mon, 17 Oct 2022 12:23:34 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id AgLAOUZJTWMRMQAAMHmgww (envelope-from ); Mon, 17 Oct 2022 12:23:34 +0000 Message-ID: Date: Mon, 17 Oct 2022 14:23:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.3.3 Subject: Re: [PATCH] gcov: support GCC 12.1 and newer compilers Content-Language: en-US To: David Laight , 'Andrew Morton' , Peter Oberparleiter Cc: "linux-kernel@vger.kernel.org" References: <624bda92-f307-30e9-9aaa-8cc678b2dfb2@suse.cz> <581f6037-ff43-4f91-cabf-d9aa0d72bbe6@linux.ibm.com> <20221016174033.d33a998b4c91b7d18b3dc310@linux-foundation.org> <9b724e2af2d048c3a7f7f20ae0942ab6@AcuMS.aculab.com> From: =?UTF-8?Q?Martin_Li=c5=a1ka?= In-Reply-To: <9b724e2af2d048c3a7f7f20ae0942ab6@AcuMS.aculab.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/17/22 13:38, David Laight wrote: > From: Andrew Morton >> Sent: 17 October 2022 01:41 > .. >> The changelog doesn't tell us what the user-visible effects of this are >> (please, it should do so), but it sounds to me like those effects are >> "gcov is utterly busted". >> >> So I'll add a cc:stable to this, so that people can use new gcc >> versions to build older kernels. > > I can't help wondering what happens if you link a binary > compiled with an old gcc with one build with a new gcc? It should be fine as the code emits each .gcda file with version that comes from the compilation phase: pos += store_gcov_u32(buffer, pos, info->version); > > This could easily happen with out of tree loadable modules. Sure. > Or just linking an old .a file into a userspace binary. > > Now maybe the gcov data isn't used (I've not looked up what > it is for) but is sounds like something whose format should > be set in stone? No, I've doing some changes to the format based on new challenges we face. Cheers, Martin > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales)