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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 63C46C433E0 for ; Fri, 12 Jun 2020 01:55:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 37527206DC for ; Fri, 12 Jun 2020 01:55:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gh8oa1er" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726265AbgFLBzs (ORCPT ); Thu, 11 Jun 2020 21:55:48 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:40537 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726305AbgFLBzr (ORCPT ); Thu, 11 Jun 2020 21:55:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591926946; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=c4mIHNftRpH04Gb26NauuDlA6dFJVkSoOuOAWxEtdVY=; b=gh8oa1ertp01y6wwTvyvA8fSl8gd5SAJSA0PWejjLuSkWvnnyUxzzUmxfc3gevT8RGOZ39 gJPAV0BFibLatBgCjzmgPhDTPDiIe9vpv5Q8Q7gTUlMyts8PBZSBBN3WVlNARImOxOXTP9 /Py3065X8jqdDT06CQTEUTFIPDqS5D8= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-298-vym_GQzPOLq4WljfY1DDsA-1; Thu, 11 Jun 2020 21:55:41 -0400 X-MC-Unique: vym_GQzPOLq4WljfY1DDsA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D8E11EC1BD; Fri, 12 Jun 2020 01:55:28 +0000 (UTC) Received: from llong.remote.csb (ovpn-115-149.rdu2.redhat.com [10.10.115.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5F8219CA0; Fri, 12 Jun 2020 01:55:24 +0000 (UTC) Subject: Re: possible deadlock in send_sigio To: Boqun Feng Cc: Peter Zijlstra , Dmitry Vyukov , syzbot , Alexey Dobriyan , Andrew Morton , allison@lohutok.net, areber@redhat.com, aubrey.li@linux.intel.com, Andrei Vagin , Bruce Fields , Christian Brauner , cyphar@cyphar.com, "Eric W. Biederman" , Greg Kroah-Hartman , guro@fb.com, Jeff Layton , Joel Fernandes , Kees Cook , linmiaohe@huawei.com, linux-fsdevel , LKML , Michal Hocko , Ingo Molnar , Oleg Nesterov , sargun@sargun.me, syzkaller-bugs , Thomas Gleixner , Al Viro References: <000000000000760d0705a270ad0c@google.com> <69818a6c-7025-8950-da4b-7fdc065d90d6@redhat.com> <88c172af-46df-116e-6f22-b77f98803dcb@redhat.com> <20200611142214.GI2531@hirez.programming.kicks-ass.net> <20200611235526.GC94665@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net> From: Waiman Long Organization: Red Hat Message-ID: <5fd58ce3-03f4-7529-e5c5-858222cd3ac2@redhat.com> Date: Thu, 11 Jun 2020 21:55:23 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200611235526.GC94665@debian-boqun.qqnc3lrjykvubdpftowmye0fmh.lx.internal.cloudapp.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/11/20 7:55 PM, Boqun Feng wrote: > Hi Peter and Waiman, > > On Thu, Jun 11, 2020 at 12:09:59PM -0400, Waiman Long wrote: >> On 6/11/20 10:22 AM, Peter Zijlstra wrote: >>> On Thu, Jun 11, 2020 at 09:51:29AM -0400, Waiman Long wrote: >>> >>>> There was an old lockdep patch that I think may address the issue, but was >>>> not merged at the time. I will need to dig it out and see if it can be >>>> adapted to work in the current kernel. It may take some time. >>> Boqun was working on that; I can't remember what happened, but ISTR it >>> was shaping up nice. >>> >> Yes, I am talking about Boqun's patch. However, I think he had moved to >> another company and so may not be able to actively work on that again. >> > I think you are talking about the rescursive read deadlock detection > patchset: > > https://lore.kernel.org/lkml/20180411135110.9217-1-boqun.feng@gmail.com/ > > Let me have a good and send a new version based on today's master of tip > tree. > > Regards, > Boqun Good to hear back from you. I thought you may not able to work on it again. Cheers, Longman