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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 EB474C2D0BF for ; Mon, 16 Dec 2019 18:10:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C567A20CC7 for ; Mon, 16 Dec 2019 18:10:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576519854; bh=w8DpnLIqefWHHbyN99Kdhz6nhOOdKYSGyPbX7mF7uQk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=bkgcgo6kcDYVuN3/fBF741nMJpHGn2qcn0Hi3fSOMq5oDYJh+4rLBAAMPVlBBMqsL 2J4zzVW5fSI5Fd9CAHUr+1NCiTuWpDZhGzdyA8CNZbLfKYG6CARtv9DbfH70xv3a/J WAaM+LXBq16ksbij5Z74IX2AKdeUZk30Ugq8nFeI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730665AbfLPSKx (ORCPT ); Mon, 16 Dec 2019 13:10:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:54322 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730318AbfLPSKw (ORCPT ); Mon, 16 Dec 2019 13:10:52 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D3500206B7; Mon, 16 Dec 2019 18:10:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576519852; bh=w8DpnLIqefWHHbyN99Kdhz6nhOOdKYSGyPbX7mF7uQk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=09W6uUf4s+kgMI1lJo/faNzSxXHxBsTXxqAporPbTnqTngKmLXy9kIh8hqukhNit4 ik9WDdv4Gnh5kT24+DQ7r+j95604Moek5yCzBuJEN4zfMnYZw3nJMfZoa2QSNhqnLR CTLq4JXaZEcfUPvA55Vlvj5Ce2k30JDhApNaOTkA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Madhavan Srinivasan , "Hariharan T.S." , Michael Ellerman Subject: [PATCH 5.3 095/180] powerpc/perf: Disable trace_imc pmu Date: Mon, 16 Dec 2019 18:48:55 +0100 Message-Id: <20191216174835.132489608@linuxfoundation.org> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20191216174806.018988360@linuxfoundation.org> References: <20191216174806.018988360@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Madhavan Srinivasan commit 249fad734a25889a4f23ed014d43634af6798063 upstream. When a root user or a user with CAP_SYS_ADMIN privilege uses any trace_imc performance monitoring unit events, to monitor application or KVM threads, it may result in a checkstop (System crash). The cause is frequent switching of the "trace/accumulation" mode of the In-Memory Collection hardware (LDBAR). This patch disables the trace_imc PMU unit entirely to avoid triggering the checkstop. A future patch will reenable it at a later stage once a workaround has been developed. Fixes: 012ae244845f ("powerpc/perf: Trace imc PMU functions") Cc: stable@vger.kernel.org # v5.2+ Signed-off-by: Madhavan Srinivasan Tested-by: Hariharan T.S. [mpe: Add pr_info_once() so dmesg shows the PMU has been disabled] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191118034452.9939-1-maddy@linux.vnet.ibm.com Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/powernv/opal-imc.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) --- a/arch/powerpc/platforms/powernv/opal-imc.c +++ b/arch/powerpc/platforms/powernv/opal-imc.c @@ -285,7 +285,14 @@ static int opal_imc_counters_probe(struc domain = IMC_DOMAIN_THREAD; break; case IMC_TYPE_TRACE: - domain = IMC_DOMAIN_TRACE; + /* + * FIXME. Using trace_imc events to monitor application + * or KVM thread performance can cause a checkstop + * (system crash). + * Disable it for now. + */ + pr_info_once("IMC: disabling trace_imc PMU\n"); + domain = -1; break; default: pr_warn("IMC Unknown Device type \n");