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=-5.2 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 252A8C5CFFE for ; Mon, 10 Dec 2018 14:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DFD362082F for ; Mon, 10 Dec 2018 14:48:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="DiR5MEZW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DFD362082F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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 S1728084AbeLJOsB (ORCPT ); Mon, 10 Dec 2018 09:48:01 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:40374 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726888AbeLJOsA (ORCPT ); Mon, 10 Dec 2018 09:48:00 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=I46PdXLQPzcr9rLDYSmTtJ9NEqenJEAYhW/gbZ1FkUU=; b=DiR5MEZWaI3unjmg6O+L22dHe DEW0TxK/+VsuUYAyfQwlks33ahMQjHcTY340O6wfHx7Sf5bzPCAFb53o9ssXhd0e9T6LWGkU5lyvP s6M1YFN0qfQxsEe4rCQpOFMjijWSmQVtRDsAZa36MZymECxSwCC51ila9zYJ8EsaQ7c1CbidifBiL DBkVozmLZFJ2UyEzz3OcADDbcwscFAjV4ADQNHoqEOk7O5bv18ko1ca5NiyflBAQQJaj3x3TkBrOC wMTMmhR6jRtmKabbtGOn+mKGNUJCAfB5FctvYHpv9TgqWCI5l+3OMl39e/zJ8SLC/7kQlCNNmnv22 YUXZL/Vfw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWMqh-0007dV-T1; Mon, 10 Dec 2018 14:47:56 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 6D2592075BE7B; Mon, 10 Dec 2018 15:47:54 +0100 (CET) Date: Mon, 10 Dec 2018 15:47:54 +0100 From: Peter Zijlstra To: Valentin Schneider Cc: Qian Cai , akpm@linux-foundation.org, mark.rutland@arm.com, marc.zyngier@arm.com, daniel.lezcano@linaro.org, tglx@linutronix.de, mingo@kernel.org, longman@redhat.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v2] clocksource/arm_arch_timer: fix a lockdep warning Message-ID: <20181210144754.GO5289@hirez.programming.kicks-ass.net> References: <1543877121-4098-1-git-send-email-cai@gmx.us> <20181210135228.49751-1-cai@lca.pw> <20181210140703.GM5289@hirez.programming.kicks-ass.net> <9303a6cf-24af-2f31-9fbd-8c1ecdd5e4f4@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9303a6cf-24af-2f31-9fbd-8c1ecdd5e4f4@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 10, 2018 at 02:19:53PM +0000, Valentin Schneider wrote: > Hi, > > On 10/12/2018 14:07, Peter Zijlstra wrote: > [...] > > --- > > kernel/cpu.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/kernel/cpu.c b/kernel/cpu.c > > index 91d5c38eb7e5..e1ee8caf28b5 100644 > > --- a/kernel/cpu.c > > +++ b/kernel/cpu.c > > @@ -313,6 +313,8 @@ void cpus_write_unlock(void) > > > > void lockdep_assert_cpus_held(void) > > { > > + if (system_state < SYSTEM_RUNNING) > > + return; > > percpu_rwsem_assert_held(&cpu_hotplug_lock); > > } > > > > Kinda hijacking the thread here - is that something we'd want to replace > > 40fa3780bac2 ("sched/core: Take the hotplug lock in sched_init_smp()") > > with? > Possibly; and I have vague memories of other people running into this same thing too.