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 BC67CC433E0 for ; Thu, 11 Jun 2020 16:10:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9A0C82078D for ; Thu, 11 Jun 2020 16:10:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="NRXJi5vE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726563AbgFKQKT (ORCPT ); Thu, 11 Jun 2020 12:10:19 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:32764 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726279AbgFKQKS (ORCPT ); Thu, 11 Jun 2020 12:10:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1591891817; 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=sAc8K5GdtWCdfeiweUngiX2JdslVVBJ6iUtA5e6N5iA=; b=NRXJi5vEBLkFARze69W1aPbmWNEugncDJkNkU22TBtE5y6F8PJVZd+lUcZVs5VIG6+WBj+ BrLB7332V62+Fwve6z2F8ygQnZZb7Xbt+/UToXawU/QdlsrRc2co48nmY0XkrJUkgfRKm3 +wof2dh2NZnZIzdPOk5LGUmKTA/3SGU= 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-122-HVzvVuaIPNaCw67pkCMHGA-1; Thu, 11 Jun 2020 12:10:12 -0400 X-MC-Unique: HVzvVuaIPNaCw67pkCMHGA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A6776107ACCA; Thu, 11 Jun 2020 16:10:08 +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 2C2655C1B0; Thu, 11 Jun 2020 16:10:00 +0000 (UTC) Subject: Re: possible deadlock in send_sigio To: Peter Zijlstra Cc: 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 , Boqun Feng 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> From: Waiman Long Organization: Red Hat Message-ID: Date: Thu, 11 Jun 2020 12:09:59 -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: <20200611142214.GI2531@hirez.programming.kicks-ass.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 10.5.11.16 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Cheers, Longman