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 A62CFECE58E for ; Wed, 9 Oct 2019 13:27:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7328D21D7E for ; Wed, 9 Oct 2019 13:27:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7328D21D7E 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 09FE28E0005; Wed, 9 Oct 2019 09:27:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0502D8E0003; Wed, 9 Oct 2019 09:27:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EA8B18E0005; Wed, 9 Oct 2019 09:27:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0005.hostedemail.com [216.40.44.5]) by kanga.kvack.org (Postfix) with ESMTP id C830F8E0003 for ; Wed, 9 Oct 2019 09:27:49 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id 66BF2824CA30 for ; Wed, 9 Oct 2019 13:27:49 +0000 (UTC) X-FDA: 76024323858.29.bone07_615b080efb647 X-HE-Tag: bone07_615b080efb647 X-Filterd-Recvd-Size: 3286 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Wed, 9 Oct 2019 13:27:48 +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 2CFDCAC6E; Wed, 9 Oct 2019 13:27:47 +0000 (UTC) Date: Wed, 9 Oct 2019 15:27:46 +0200 From: Michal Hocko To: Qian Cai Cc: Petr Mladek , Christian Borntraeger , Heiko Carstens , sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, akpm@linux-foundation.org, Vasily Gorbik , Peter Oberparleiter , david@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Message-ID: <20191009132746.GA6681@dhcp22.suse.cz> References: <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> <20191008191728.GS6681@dhcp22.suse.cz> <1570563324.5576.309.camel@lca.pw> <20191009114903.aa6j6sa56z2cssom@pathway.suse.cz> <1570626402.5937.1.camel@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1570626402.5937.1.camel@lca.pw> User-Agent: Mutt/1.10.1 (2018-07-13) Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000064, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 09-10-19 09:06:42, Qian Cai wrote: [...] > https://lore.kernel.org/linux-mm/1570460350.5576.290.camel@lca.pw/ >=20 > [=A0=A0297.425964] -> #1 (&port_lock_key){-.-.}: > [=A0=A0297.425967]=A0=A0=A0=A0=A0=A0=A0=A0__lock_acquire+0x5b3/0xb40 > [=A0=A0297.425967]=A0=A0=A0=A0=A0=A0=A0=A0lock_acquire+0x126/0x280 > [=A0=A0297.425968]=A0=A0=A0=A0=A0=A0=A0=A0_raw_spin_lock_irqsave+0x3a/0= x50 > [=A0=A0297.425969]=A0=A0=A0=A0=A0=A0=A0=A0serial8250_console_write+0x3e= 4/0x450 > [=A0=A0297.425970]=A0=A0=A0=A0=A0=A0=A0=A0univ8250_console_write+0x4b/0= x60 > [=A0=A0297.425970]=A0=A0=A0=A0=A0=A0=A0=A0console_unlock+0x501/0x750 > [=A0=A0297.425971]=A0=A0=A0=A0=A0=A0=A0=A0vprintk_emit+0x10d/0x340 > [=A0=A0297.425972]=A0=A0=A0=A0=A0=A0=A0=A0vprintk_default+0x1f/0x30 > [=A0=A0297.425972]=A0=A0=A0=A0=A0=A0=A0=A0vprintk_func+0x44/0xd4 > [=A0=A0297.425973]=A0=A0=A0=A0=A0=A0=A0=A0printk+0x9f/0xc5 > [=A0=A0297.425974]=A0=A0=A0=A0=A0=A0=A0=A0register_console+0x39c/0x520 > [=A0=A0297.425975]=A0=A0=A0=A0=A0=A0=A0=A0univ8250_console_init+0x23/0x= 2d > [=A0=A0297.425975]=A0=A0=A0=A0=A0=A0=A0=A0console_init+0x338/0x4cd > [=A0=A0297.425976]=A0=A0=A0=A0=A0=A0=A0=A0start_kernel+0x534/0x724 > [=A0=A0297.425977]=A0=A0=A0=A0=A0=A0=A0=A0x86_64_start_reservations+0x2= 4/0x26 > [=A0=A0297.425977]=A0=A0=A0=A0=A0=A0=A0=A0x86_64_start_kernel+0xf4/0xfb > [=A0=A0297.425978]=A0=A0=A0=A0=A0=A0=A0=A0secondary_startup_64+0xb6/0xc= 0 >=20 > where=A0the report again show the early boot call trace for the locking > dependency, >=20 > console_owner --> port_lock_key >=20 > but that dependency clearly not only happen in the early boot. Can you provide an example of the runtime dependency without any early boot artifacts? Because this discussion really doens't make much sense without a clear example of a _real_ lockdep report that is not a false possitive. All of them so far have been concluded to be false possitive AFAIU. --=20 Michal Hocko SUSE Labs