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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 06B59C5CFE7 for ; Wed, 11 Jul 2018 11:24:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEF8A20835 for ; Wed, 11 Jul 2018 11:24:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BEF8A20835 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732824AbeGKL2m (ORCPT ); Wed, 11 Jul 2018 07:28:42 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:33700 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732586AbeGKL2k (ORCPT ); Wed, 11 Jul 2018 07:28:40 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 54B04168F; Wed, 11 Jul 2018 04:24:49 -0700 (PDT) Received: from usa.arm.com (unknown [10.1.210.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 6A97D3F589; Wed, 11 Jul 2018 04:24:48 -0700 (PDT) From: Sudeep Holla To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Sudeep Holla , Thomas Gleixner Subject: [PATCH 3/3] clockevents: warn if cpu_all_mask is used for cpumask while registering new device Date: Wed, 11 Jul 2018 12:24:24 +0100 Message-Id: <1531308264-24220-3-git-send-email-sudeep.holla@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1531308264-24220-1-git-send-email-sudeep.holla@arm.com> References: <1531308264-24220-1-git-send-email-sudeep.holla@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using cpu_all_mask in clockevents cpumask may result in issues while comparing multiple clockevent devices to choose the preferred one. On one of the platforms with 2 system(i.e. non per-CPU) timers with different ratings, having cpu_all_mask for one of the device resulted in boot hang with forever loop in clockevents_notify_released as both were being selected as preferred. In order to prevent such issues in future, let's warn if any clockevent drivers sets cpu_all_mask as it's cpumask and just override it to use cpu_possible_mask. All the existing occurrences of cpu_all_mask are already replaced with cpu_possible_mask. Cc: Thomas Gleixner Signed-off-by: Sudeep Holla --- kernel/time/clockevents.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index 16c027e9cc73..8c0e4092f661 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -463,6 +463,12 @@ void clockevents_register_device(struct clock_event_device *dev) dev->cpumask = cpumask_of(smp_processor_id()); } + if (dev->cpumask == cpu_all_mask) { + WARN(1, "%s cpumask == cpu_all_mask, using cpu_possible_mask instead\n", + dev->name); + dev->cpumask = cpu_possible_mask; + } + raw_spin_lock_irqsave(&clockevents_lock, flags); list_add(&dev->list, &clockevent_devices); -- 2.7.4