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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1025C31E40 for ; Mon, 10 Jun 2019 17:15:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B24D2207E0 for ; Mon, 10 Jun 2019 17:15:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387741AbfFJRPy (ORCPT ); Mon, 10 Jun 2019 13:15:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36696 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725270AbfFJRPx (ORCPT ); Mon, 10 Jun 2019 13:15:53 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6DF71C057E37; Mon, 10 Jun 2019 17:15:48 +0000 (UTC) Received: from prarit.khw1.lab.eng.bos.redhat.com (prarit-guest.khw1.lab.eng.bos.redhat.com [10.16.200.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7DA905C1B4; Mon, 10 Jun 2019 17:15:46 +0000 (UTC) From: Prarit Bhargava To: linux-kernel@vger.kernel.org Cc: Prarit Bhargava , Fenghua Yu , Reinette Chatre , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , x86@kernel.org Subject: [PATCH] x86/resctrl: Fix panic on systems that do not enable local MBM Date: Mon, 10 Jun 2019 13:15:44 -0400 Message-Id: <20190610171544.13474-1-prarit@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Mon, 10 Jun 2019 17:15:53 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Booting with kernel parameter "rdt=cmt,mbmtotal,memlocal,l3cat,mba" and executing "mount -t resctrl resctrl -o mba_MBps /sys/fs/resctrl" results in a panic on systems without local MBM support enabled in firmware. BUG: kernel NULL pointer dereference, address: 0000000000000020 PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 722 Comm: kworker/0:3 Not tainted 5.2.0-0.rc3.git0.1.el7_UNSUPPORTED.x86_64 #2 Hardware name: Dell Inc. PowerEdge R740/0923K0, BIOS 2.1.8 04/30/2019 Workqueue: events mbm_handle_overflow RIP: 0010:mbm_handle_overflow+0x150/0x2b0 Only call the bandwith update loop if the system has local MBM enabled. Signed-off-by: Prarit Bhargava Cc: Fenghua Yu Cc: Reinette Chatre Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: "H. Peter Anvin" Cc: x86@kernel.org --- arch/x86/kernel/cpu/resctrl/monitor.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index 7ee93125a211..397206f23d14 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -360,6 +360,9 @@ static void update_mba_bw(struct rdtgroup *rgrp, struct rdt_domain *dom_mbm) struct list_head *head; struct rdtgroup *entry; + if (!is_mbm_local_enabled()) + return; + r_mba = &rdt_resources_all[RDT_RESOURCE_MBA]; closid = rgrp->closid; rmid = rgrp->mon.rmid; -- 2.21.0