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=-2.4 required=3.0 tests=DKIM_SIGNED, MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID,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 9B403C4321D for ; Tue, 21 Aug 2018 16:00:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 486112177F for ; Tue, 21 Aug 2018 16:00:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BY4spPul" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 486112177F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.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 S1728203AbeHUTVY (ORCPT ); Tue, 21 Aug 2018 15:21:24 -0400 Received: from mail-yw1-f67.google.com ([209.85.161.67]:36138 "EHLO mail-yw1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727650AbeHUTVY (ORCPT ); Tue, 21 Aug 2018 15:21:24 -0400 Received: by mail-yw1-f67.google.com with SMTP id w202-v6so2203679yww.3; Tue, 21 Aug 2018 09:00:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=P4/VzEQA4DDqzq9gejGOYdmW+pT3MXxoLZ3rK2bSw/c=; b=BY4spPulfmCbg1mA9q2uxKWDQZM9S8fEsx8JUUFDDrz0yrnM3qDq5YG2CXDdHC9FN6 HRrc8gXLWmdzJ94/eooTXZFciCVT55WCP4izE458+RCVDpp+vPN6nQTeQ6mHjl3Ufhfr 5xdbXtGSK0yQiA00qRxtf7eACw+JEZ/b/evJIIhNgZnJMlRxooyEZY8o/FNKmNplF3W0 WWm5QgN7WW4199MKKi/kR6ZhS8d3VPSLlvXPR/hn33xxuH0hZbIoYpxZhjBpSvvHrbiH JYOZv0bxQVvqlmE/mz+ipS2TEdrTUGrlmHpGvq9wDthLcRoJjv6IgLcK7mBEhT9d9Udb nf9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=P4/VzEQA4DDqzq9gejGOYdmW+pT3MXxoLZ3rK2bSw/c=; b=rSkSws5R8FwAmuL/C/hnN+Bf9hkTJiLzqmF5btCJzngmfyr5Ic7dCmpLIT9jGisyUx MrD9kQNEPZffIEROhw+7CECV0q1ZEaLUy8Ouw1UYjq2MsvbUcEe8dk4aLAJTwkF32tR5 AWSRNFEwBneeyJA6J7pi0Q4D8STfaVIM4PRoNyTQw24xt5IoBsMMah68tksj0JQvkS2G cg8DJmPbC4QjZf0DtZnwtmCuCDigbadEsg14/MF3NPpRrKsfpJyxjNKR5U3k+JGV5FbS LPxkFoQKKjbxiYP65fmV7HGUUefBJaCjdpbdim5jLHgTwlX3MzG6kYmIdIW/NRZDMsMz OfPA== X-Gm-Message-State: AOUpUlGI6iN77Q8OJhO06TUrx84WmHv4xhS63lEfnX0cGShAnAnZyG1q N4RVVirnm7nGnu/K8epPzLw= X-Google-Smtp-Source: AA+uWPx8CG2BJXtHw2NM3/BnyqA/247/gznx+OkyvHAidnqeyKvxNMUX2LHws8DLNy3RSeF2MMEPWg== X-Received: by 2002:a81:148f:: with SMTP id 137-v6mr27514692ywu.97.1534867241373; Tue, 21 Aug 2018 09:00:41 -0700 (PDT) Received: from localhost ([2620:10d:c091:200::1:9c5d]) by smtp.gmail.com with ESMTPSA id k9-v6sm6059512ywh.33.2018.08.21.09.00.40 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 Aug 2018 09:00:40 -0700 (PDT) Date: Tue, 21 Aug 2018 09:00:39 -0700 From: Tejun Heo To: Johannes Berg Cc: Lai Jiangshan , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org Subject: Re: [PATCH 0/2] workqueue lockdep limitations/bugs Message-ID: <20180821160039.GO3978217@devbig004.ftw2.facebook.com> References: <20180821120317.4115-1-johannes@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180821120317.4115-1-johannes@sipsolutions.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Johannes. On Tue, Aug 21, 2018 at 02:03:15PM +0200, Johannes Berg wrote: > 3) > The third problem is more complicated, but it means that we likely miss a > lot of potential locking problems with ordered workqueues, and I think we > should really try to fix this somehow. > > Let's say we again have an ordered workqueue, and the following: > > work1_function > { > mutex_lock(&mutex); > } Regular mutexes complain when the locker isn't the unlocker already. Do we really care about this case? Thanks. -- tejun