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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 682FFC43331 for ; Fri, 3 Apr 2020 14:54:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 398D520719 for ; Fri, 3 Apr 2020 14:54:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1585925663; bh=aByPsR1xstQ+1gE/4RBD/d5iXCyyuPTcT26epCM5OcA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=y38Qpdm3QdssrYkeQUwR7tiNS4t+9EeqX2Kf+gF20mAASSY/O3tXtggQspiF4hT9J Xslz0A5DxMd3S0ghrxMsRB4T9fnd1qWFUxtRfPspu+eGKQLfpw1F+5TSYDNA2+Xok2 tWcD96VYYM+49+5Af6j3RV8ynSO8QjLBSHsgABIQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404001AbgDCOyW (ORCPT ); Fri, 3 Apr 2020 10:54:22 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:45978 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727431AbgDCOyV (ORCPT ); Fri, 3 Apr 2020 10:54:21 -0400 Received: by mail-qk1-f194.google.com with SMTP id o18so5378774qko.12; Fri, 03 Apr 2020 07:54:21 -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:content-transfer-encoding:in-reply-to; bh=Qyus9wEurAIsnv0KktXUQAPVSjugd3/P/58Fl3RicEU=; b=AsMjO4gFG/KXUlzlax7BKYVPEzhqXKQC1Xgj+6ktBQX8c79pf9D9fDvjN0PhCoBALB NYUDhQGz+MFxBY/tKwUkORWhVJPah3s36fFIe1usQXybxHqknrWgb5LGQopO7mDMwt9s 13PIz1GKaNUteJUiZr2asCr+CwNxf/FALTr+MP6W0AcE3pvVmgltqKj+MVNIP6QzaUzF vyBN0pHykga9tV1YgB6OqZy9QlylEz2/psehTECYZtoRFA+proI997MDHcKhy3Su8HJz dv7wL63P4+DjSgV/KuLlWlKFoiQ+EEZI3keIoEGHiKIoEcRVx9H8q8cDQWx4re3y3U38 +9Mg== 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 :content-transfer-encoding:in-reply-to; bh=Qyus9wEurAIsnv0KktXUQAPVSjugd3/P/58Fl3RicEU=; b=LnMjSrSAL3wX/KDmCDXFXVm3Q9VkcJoGrGPIp5CcIJUq95WZHc/cJHChLn22KpKCdW pWc3bG1Pc1reH1TFoH73eXKatT65vGkG08SOCk5r1c+TdDo23kFZiCOhKUop4cZnmxC/ lrELl1pBQpJ9wjRLBZhPMKZIsu6pPpHSYyBTNsnepclC9aIaL7KC0Hb3b23quXq3paw+ uwH8QlCswKzVPr+ZCvSeDmENymL5oTBEbPyJ9rfqVv/EVNVWEO48nRzrfO+IvqyFiwXF 7tjLSkcDFg347Sy41EhiNGSsqarFV1fIkVjAYM0R5NUAFVVqrURcXBiYOd6ohVFri8nJ V1/Q== X-Gm-Message-State: AGi0PuahD9iKfCKT0qToC9xpvItmORiNXkjMe4LzLfKKdVYzDTNxSfWv EWm/cLlzBfxEs5SmRTAct8Y= X-Google-Smtp-Source: APiQypJEdBPfmXOuzJ8JYh/Jyhg63+9foiTxBStOFtcR0yFpV717o79f78RVq/NBTzZk1bEtOiq+kw== X-Received: by 2002:a37:b981:: with SMTP id j123mr9347140qkf.32.1585925660957; Fri, 03 Apr 2020 07:54:20 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::842b]) by smtp.gmail.com with ESMTPSA id 79sm6421528qkg.38.2020.04.03.07.54.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Apr 2020 07:54:20 -0700 (PDT) Date: Fri, 3 Apr 2020 10:54:18 -0400 From: Tejun Heo To: Qian Cai Cc: Prateek Sood , Li Zefan , cgroups@vger.kernel.org, LKML , Peter Zijlstra Subject: Re: Deadlock due to "cpuset: Make cpuset hotplug synchronous" Message-ID: <20200403145418.GB162390@mtj.duckdns.org> References: <20200325191922.GM162390@mtj.duckdns.org> <6AD62381-394F-4742-816B-12DE67DE9788@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <6AD62381-394F-4742-816B-12DE67DE9788@lca.pw> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 01, 2020 at 10:00:31PM -0400, Qian Cai wrote: > > > > On Mar 25, 2020, at 3:19 PM, Tejun Heo wrote: > > > > On Wed, Mar 25, 2020 at 03:16:56PM -0400, Qian Cai wrote: > >> The linux-next commit a49e4629b5ed (“cpuset: Make cpuset hotplug synchronous”) > >> introduced real deadlocks with CPU hotplug as showed in the lockdep splat, since it is > >> now making a relation from cpu_hotplug_lock —> cgroup_mutex. > > > > Prateek, can you please take a look? Given that the merge window is just around > > the corner, we might have to revert and retry later if it can't be resolved > > quickly. > > Tejun, can you back off this commit now given it seems nobody is trying to rescue it? Yeah, gonna revert it before sending out the pull request. Thanks. -- tejun