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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,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 48987C43441 for ; Fri, 9 Nov 2018 17:41:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1686C2081C for ; Fri, 9 Nov 2018 17:41:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1686C2081C 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 S1728581AbeKJDXH (ORCPT ); Fri, 9 Nov 2018 22:23:07 -0500 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:35564 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727961AbeKJDXG (ORCPT ); Fri, 9 Nov 2018 22:23:06 -0500 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 6078FA78; Fri, 9 Nov 2018 09:41:30 -0800 (PST) Received: from [10.1.196.62] (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 110B43F718; Fri, 9 Nov 2018 09:41:27 -0800 (PST) Subject: Re: WARNING: CPU: 0 PID: 0 at drivers/irqchip/irq-gic-v3-its.c To: Sudeep Holla Cc: cai@gmx.us, open list , Thomas Gleixner , ard.biesheuvel@linaro.org, Jason Cooper References: <1541710771.12945.7.camel@gmx.us> <13A11479-97FB-4EFD-A182-61DA63CB64D6@gmx.us> <930d61db-6e44-8501-983d-09cd3759d153@arm.com> From: Marc Zyngier Openpgp: preference=signencrypt Autocrypt: addr=marc.zyngier@arm.com; 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Linux aarch64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/11/18 17:28, Sudeep Holla wrote: > On Fri, Nov 9, 2018 at 4:10 PM Marc Zyngier wrote: >> > [...] > >> >> See bb42ca474010 and d003d029cea8 for details. >> >> Now, activating this workaround leads to lockdep being really angry, >> most likely because the cpus_read_lock is not taken, which is a change >> in behaviour... >> >> I'm trying to dig into this now. >> > > Yes we found similar issue in kernel/sched/core.c sched_init_smp > There's a fix with detailed description in -next > (Commit 40fa3780bac2 ("sched/core: Take the hotplug lock in sched_init_smp()") > > The behaviour changed since commit cb538267ea1e ("jump_label/lockdep: > Assert we hold the hotplug lock for _cpuslocked() operations") I indeed came to the same conclusion, but the fix is slightly less than obvious. I have the following arm64-specific crap, but it is pretty terrible: diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c index f258636273c9..9e96e9eaca9b 100644 --- a/arch/arm64/kernel/time.c +++ b/arch/arm64/kernel/time.c @@ -36,6 +36,7 @@ #include #include #include +#include #include @@ -69,7 +70,9 @@ void __init time_init(void) u32 arch_timer_rate; of_clk_init(NULL); + cpus_read_lock(); timer_probe(); + cpus_read_unlock(); tick_setup_hrtimer_broadcast(); Qian, can you please let me know if this helps? If it does, we'll have to think of something a bit better... Thanks, M. -- Jazz is not dead. It just smells funny...