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=-14.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 54FB2C2B9F4 for ; Thu, 17 Jun 2021 07:34:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 39F17613CB for ; Thu, 17 Jun 2021 07:34:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229805AbhFQHgt (ORCPT ); Thu, 17 Jun 2021 03:36:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:36252 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbhFQHgt (ORCPT ); Thu, 17 Jun 2021 03:36:49 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (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 0D867613BF; Thu, 17 Jun 2021 07:34:42 +0000 (UTC) Received: from sofa.misterjones.org ([185.219.108.64] helo=why.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ltmXw-0087db-35; Thu, 17 Jun 2021 08:34:40 +0100 Date: Thu, 17 Jun 2021 08:34:35 +0100 Message-ID: <87r1h1c5bo.wl-maz@kernel.org> From: Marc Zyngier To: Greg Kroah-Hartman Cc: Aman Priyadarshi , Will Deacon , Alexander Graf , Mark Rutland , stable@vger.kernel.org, Ali Saidi Subject: Re: [PATCH] arm64: perf: Disable PMU while processing counter overflows In-Reply-To: References: <20210616192859.21708-1-apeureka@amazon.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/27.1 (x86_64-pc-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: gregkh@linuxfoundation.org, apeureka@amazon.de, will@kernel.org, graf@amazon.de, mark.rutland@arm.com, stable@vger.kernel.org, alisaidi@amazon.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Thu, 17 Jun 2021 05:51:03 +0100, Greg Kroah-Hartman wrote: > > On Wed, Jun 16, 2021 at 09:28:59PM +0200, Aman Priyadarshi wrote: > > From: Suzuki K Poulose > > > > [ Upstream commit 3cce50dfec4a5b0414c974190940f47dd32c6dee ] > > > > The arm64 PMU updates the event counters and reprograms the > > counters in the overflow IRQ handler without disabling the > > PMU. This could potentially cause skews in for group counters, > > where the overflowed counters may potentially loose some event > > counts, while they are reprogrammed. To prevent this, disable > > the PMU while we process the counter overflows and enable it > > right back when we are done. > > > > This patch also moves the PMU stop/start routines to avoid a > > forward declaration. > > > > Suggested-by: Mark Rutland > > Cc: Will Deacon > > Acked-by: Mark Rutland > > Signed-off-by: Suzuki K Poulose > > Signed-off-by: Will Deacon > > Signed-off-by: Aman Priyadarshi > > Cc: stable@vger.kernel.org > > --- > > arch/arm64/kernel/perf_event.c | 50 +++++++++++++++++++--------------- > > 1 file changed, 28 insertions(+), 22 deletions(-) > > What stable tree(s) do you want this applied to? I guess that'd be 4.14 and previous stables if the patch actually applies. Thanks, M. -- Without deviation from the norm, progress is not possible.