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 7DF57C00A5A for ; Thu, 19 Jan 2023 15:19:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230353AbjASPTA (ORCPT ); Thu, 19 Jan 2023 10:19:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55928 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230379AbjASPSq (ORCPT ); Thu, 19 Jan 2023 10:18:46 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E1EF18298E for ; Thu, 19 Jan 2023 07:18:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=26Vzdfk8IdehtEF8twTCYdwKeIkT3v/NB65Q8/opuvU=; b=wKnaZKGv244sKaa5/MbOQalVW2 +GNCgmvInCTBakotr37QLjo2O17nERiNMWouC04X0XvwzhQeQ2HRBa7Ky/ZxAe113ULLv+Cv6837Z e1dBTnnlf1nFWPcD5lB2UBtS1LcRKFSukIJl470uUNgWbbFbx0aAxpzf5CsHykGzFNcM7Xl1aiqAM SxM3rRtS9MJ3w7eF8P0G2jPScLimVe6bLDg2N3s47NBDsuBkpqOH/2djIM61pojKRKLFCiAX+TSYP o4Eagk+2oqsLMmCznNVhTx53iOScKpvk4OvLG3eU6X2XSQziFg4gSg9NrbgPMnvnIkc4nALyjBn+s L1o/ho/Q==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1pIWgV-00158f-Pv; Thu, 19 Jan 2023 15:18:36 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3F9AA30008D; Thu, 19 Jan 2023 16:18:34 +0100 (CET) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 243BF20DC30B7; Thu, 19 Jan 2023 16:18:34 +0100 (CET) Date: Thu, 19 Jan 2023 16:18:34 +0100 From: Peter Zijlstra To: "Erhard F." Cc: sandipan.das@amd.com, linux-kernel@vger.kernel.org Subject: Re: [bisected] clang 15 built kernel fails to boot, stuck at "Loading Linux 6.1.1 ...", gcc 12 built kernel with same config boots fine Message-ID: References: <20230119022303.177052e4@yea> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 19, 2023 at 02:56:08PM +0100, Peter Zijlstra wrote: > On Thu, Jan 19, 2023 at 02:23:03AM +0100, Erhard F. wrote: > > Hi! > > > > I did a kernel bisect for an issue I originally posted on https://github.com/ClangBuiltLinux/linux/issues/1774 > > > > It is about kernel 6.1.x not booting on my machines when built with clang. A gcc built kernel with the same config just works fine. Turns out kernel v6.2-rc4 and earlier v6.2-rc are still affected. > > > > I did a kernel bisect which revealed this commit: > > > > # git bisect bad > > 706460a96fc654e80b6bed1f562b00d2ce9f2f4d is the first bad commit > > commit 706460a96fc654e80b6bed1f562b00d2ce9f2f4d > > Author: Sandipan Das > > Date: Thu Aug 11 17:59:51 2022 +0530 > > > > perf/x86/amd/core: Add generic branch record interfaces > > > > AMD processors that are capable of recording branches support either Branch > > Sampling (BRS) or Last Branch Record (LBR). In preparation for adding Last > > Branch Record Extension Version 2 (LbrExtV2) support, introduce new static > > calls which act as gateways to call into the feature-dependent functions > > based on what is available on the processor. > > > > Signed-off-by: Sandipan Das > > Signed-off-by: Peter Zijlstra (Intel) > > Link: https://lore.kernel.org/r/b75dbc32663cb395f0d701167e952c6a6b0445a3.1660211399.git.sandipan.das@amd.com > > > > arch/x86/events/amd/core.c | 34 ++++++++++++++++++++++------------ > > 1 file changed, 22 insertions(+), 12 deletions(-) > > Using: v6.2-rc4-67-g7287904c8771 > > I have an AMD Interlagos and after bringing it back to live/up-to-date I > can't seem to even boot your .config in qemu/kvm irrespective of > GCC/Clang. > > When I build defconfig+kvm_guest.config both GCC-12 and clang-15 boot > just fine in qemu/kvm. Furthermore, testing localyesconfig based off Debian's config-6.1.0-1-amd64 boots fine using both GCC-12 and clang-15 as host kernels on that machine.