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 92096C433F5 for ; Thu, 5 May 2022 23:18:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383122AbiEEXWg (ORCPT ); Thu, 5 May 2022 19:22:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57620 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235676AbiEEXWe (ORCPT ); Thu, 5 May 2022 19:22:34 -0400 Received: from smtp-relay-canonical-0.canonical.com (smtp-relay-canonical-0.canonical.com [185.125.188.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BC535DBD1; Thu, 5 May 2022 16:18:51 -0700 (PDT) Received: from [192.168.1.31] (097-089-247-249.biz.spectrum.com [97.89.247.249]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-0.canonical.com (Postfix) with ESMTPSA id 253383F1AF; Thu, 5 May 2022 23:18:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1651792727; bh=VVnmPbFnA4OIRX+hXqQx9XDh1uWLf3BJMOQz6Bb6B4U=; h=Message-ID:Date:MIME-Version:Cc:From:To:Subject:Content-Type; b=QAYWDspQ0p7qfXYLaLcFNbtWR9OGuK7KfGOJNrX+DQDapPLCM8P0GXDLjJMeKvaTI I7xV1BKw/jC3askrfGgYOXKYqg3LpXL3ieB2zOjcwUsd+T82XBrgx8DpGRmWE2sfRL d9/+K55WDj3X4s8n8MBVEcTlJX1qAYB7f3+IextUr/TCDruW6lZixSS0LmMcLaBHw2 QhulImiekLFVYFO7cpAv88qQVhLLZIWM0sT6QtlbVWUy3bKz2Zajr27ynfSZm9gvsn NXWLehTYJv3GbjqNJv5tcGjrtIN+ANiacAnijj3xuq5Yr1PkbWBcT/rfq4oVaAVDBA VUEA1OZpkp6wg== Message-ID: Date: Thu, 5 May 2022 19:18:45 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.8.1 Content-Language: en-US Cc: linux-kernel@vger.kernel.org, dave.hansen@linux.intel.com, linux-rt-users@vger.kernel.org From: Joseph Salisbury To: tglx@linutronix.de Subject: Issue With real-time patches on 5.15.y Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, I ran into a build failure after applying the rt40 real-time patches[0] to an Ubuntu 22.04 kernel. The Ubuntu kernel is based on upstream stable 5.15.y(5.15.34 currently).  I believe this patch is the specific one that introduces the build issue: 0086-locking-Allow-to-include-asm-spinlock_types.h-from-l.patch. After a bisect, the following commit was identified as the cause for the build failure: b50854eca0e0 ("x86/pkru: Remove useless include") This commit was added to mainline as of 5.16-rc1 and not Cc'd to stable, so it should not exist in 5.15.y.  However, it was purposely added to the Ubuntu kernel to enable x86 AMX support[1]. The real-time kernel build failure can be resolved by reverting commit b50854eca0e0.  The failure seems to be due to the removal of an include of xstate.h from pkru.h and caused spinlock_t to not be defined.  The commit would only be reverted for the real-time kernel and not any other kernels.  I wanted to see if reverting the commit is the proper approach, or if cherry-picking additional commits might be a better solution in preparation for additional changes that might be coming in the future? Any suggestions would be greatly appreciated. Thanks, Joe [0] https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.15/older/patches-5.15.34-rt40.tar.gz [1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1967750