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=-2.5 required=3.0 tests=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 17E4BECE58C for ; Tue, 8 Oct 2019 19:17:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DAAAB21871 for ; Tue, 8 Oct 2019 19:17:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DAAAB21871 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 665A68E0005; Tue, 8 Oct 2019 15:17:33 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 616EF8E0003; Tue, 8 Oct 2019 15:17:33 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 52B108E0005; Tue, 8 Oct 2019 15:17:33 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0058.hostedemail.com [216.40.44.58]) by kanga.kvack.org (Postfix) with ESMTP id 2BC118E0003 for ; Tue, 8 Oct 2019 15:17:33 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id BB713824CA2A for ; Tue, 8 Oct 2019 19:17:32 +0000 (UTC) X-FDA: 76021576344.27.brick27_24bd331a8781d X-HE-Tag: brick27_24bd331a8781d X-Filterd-Recvd-Size: 2600 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf30.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 19:17:32 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 7F338B112; Tue, 8 Oct 2019 19:17:30 +0000 (UTC) Date: Tue, 8 Oct 2019 21:17:28 +0200 From: Michal Hocko To: Qian Cai Cc: Christian Borntraeger , Petr Mladek , Peter Oberparleiter , akpm@linux-foundation.org, sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, david@redhat.com, linux-kernel@vger.kernel.org, Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Message-ID: <20191008191728.GS6681@dhcp22.suse.cz> References: <1570228005-24979-1-git-send-email-cai@lca.pw> <20191007143002.l37bt2lzqtnqjqxu@pathway.suse.cz> <20191007144937.GO2381@dhcp22.suse.cz> <20191008074357.f33f6pbs4cw5majk@pathway.suse.cz> <20191008082752.GB6681@dhcp22.suse.cz> <1570550917.5576.303.camel@lca.pw> <20191008183525.GQ6681@dhcp22.suse.cz> <1570561573.5576.307.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1570561573.5576.307.camel@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000023, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 08-10-19 15:06:13, Qian Cai wrote: > On Tue, 2019-10-08 at 20:35 +0200, Michal Hocko wrote: [...] > > I fully agree that this class of lockdep splats are annoying especially > > when they make the lockdep unusable but please discuss this with lockdep > > maintainers and try to find some solution rather than go and try to > > workaround the problem all over the place. If there are places that > > would result in a cleaner code then go for it but please do not make the > > code worse just because of a non existent problem flagged by a false > > positive. > > It makes me wonder what make you think it is a false positive for sure. Because this is an early init code? Because if it were a real deadlock then your system wouldn't boot to get run with the real userspace (remember there is zone->lock spinlock involved and that means that you would hit hard lock after few seconds - but I feel I am repeating myself). -- Michal Hocko SUSE Labs