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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no 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 D9E94C433E7 for ; Wed, 2 Sep 2020 12:14:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B37B7206F0 for ; Wed, 2 Sep 2020 12:14:23 +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="cNHyhKqU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726323AbgIBMOU (ORCPT ); Wed, 2 Sep 2020 08:14:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726377AbgIBMOL (ORCPT ); Wed, 2 Sep 2020 08:14:11 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 150C9C061244; Wed, 2 Sep 2020 05:14:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=NadokaudFgFu9nMqgW3AlEN/gjoKd9NcBHIQBLterQc=; b=cNHyhKqUc+bx3k9nQ7UUWDCZaU S3o+RQdCG0YXb+ogIN83rwNSwWanJEnCLsxrjV8MtSAGJG1RjGRPQ3GcUaecix2yWLKI0q9Hgiyt/ JtAfRFzWy8t15wcwatM8mJr/KXTngtKdH3XlLhkh5dyNPVsWgCRIe7QkCo0YKXjp/bvq1Rr/gsCHP hXlbG7hbnps9N+UP/GAgKgl0JeD57Zbx0oZiLqNsqnVx9Pyrcz3PEGfXn9yp7vUPHG4plQsq5/CSD NK06IP8lJJjJ9NGZ4Il1Wt3x2S1pjySa6oKFp3C7y7qs/ct4VF2zYuTL55+GR8C1qENhjWzsfAndD 0NlgetLg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDReH-0007On-AX; Wed, 02 Sep 2020 12:13:57 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id BB1E93003E5; Wed, 2 Sep 2020 14:13:55 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A43C123D3D72C; Wed, 2 Sep 2020 14:13:55 +0200 (CEST) Date: Wed, 2 Sep 2020 14:13:55 +0200 From: peterz@infradead.org To: Ulf Hansson Cc: "Paul E. McKenney" , Lina Iyer , Naresh Kamboju , "Rafael J. Wysocki" , Saravana Kannan , open list , linux-mmc , lkft-triage@lists.linaro.org, rcu@vger.kernel.org, Linux PM , Anders Roxell , Arnd Bergmann , Rajendra Nayak , John Stultz , Stephen Boyd , Lars Povlsen , madhuparnabhowmik10@gmail.com, Viresh Kumar , Vincent Guittot , Thomas Gleixner Subject: Re: WARNING: suspicious RCU usage - sdhci-pltfm: SDHCI platform and OF driver helper Message-ID: <20200902121355.GE1362448@hirez.programming.kicks-ass.net> References: <20200901104206.GU1362448@hirez.programming.kicks-ass.net> <20200901154417.GD20303@codeaurora.org> <20200901155014.GF2674@hirez.programming.kicks-ass.net> <20200901161340.GC29330@paulmck-ThinkPad-P72> <20200901174216.GJ29142@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 02, 2020 at 09:03:37AM +0200, Ulf Hansson wrote: > Lots of cpuidle drivers are using CPU_PM notifiers (grep for > cpu_pm_enter and you will see) from their idlestates ->enter() > callbacks. And for those we are already calling > rcu_irq_enter_irqson|off() in cpu_pm_notify() when firing them. Yeah, that particular trainwreck is on my todo list already ... then again, that list is forever overflowing. I'm thinking cpu_pm_unregister_notifier() is not a common thing? The few I looked at seem to suggest 'never' is a good approximation. It would be fairly trivial to replace the atomic_notifier usage with a raw_notifier a lock and either stop-machine or IPIs. Better still would be if we can get rid of it entirely, but I can't tell in a hurry if that is possible.