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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 C11ECECE58E for ; Tue, 8 Oct 2019 09:32:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 73AC72070B for ; Tue, 8 Oct 2019 09:32:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="IUn06mpS" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73AC72070B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lca.pw Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D2BF28E0005; Tue, 8 Oct 2019 05:32:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CDC2D8E0003; Tue, 8 Oct 2019 05:32:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BCA9B8E0005; Tue, 8 Oct 2019 05:32:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0213.hostedemail.com [216.40.44.213]) by kanga.kvack.org (Postfix) with ESMTP id 9636F8E0003 for ; Tue, 8 Oct 2019 05:32:18 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 3E874181B0485 for ; Tue, 8 Oct 2019 09:32:18 +0000 (UTC) X-FDA: 76020101556.21.alarm33_1406d34c3c34c X-HE-Tag: alarm33_1406d34c3c34c X-Filterd-Recvd-Size: 3598 Received: from mail-qk1-f195.google.com (mail-qk1-f195.google.com [209.85.222.195]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Tue, 8 Oct 2019 09:32:17 +0000 (UTC) Received: by mail-qk1-f195.google.com with SMTP id h126so15964087qke.10 for ; Tue, 08 Oct 2019 02:32:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lca.pw; s=google; h=content-transfer-encoding:from:mime-version:subject:date:message-id :references:cc:in-reply-to:to; bh=EWJqqy29yofdCquZBPthLER+Jv293+BzSZVb1kweNlE=; b=IUn06mpS2xz7vLSozYS3LnEtGuT0KW+oZs4uibzwSg/3iNgPs9KOIeGn7NQK8fYDh7 BnHO22WND/EsUUAyk7hGQY0w92oRpeiX21uNyO0lCj/9StMJBNCkYum35KnmCUGPl5gt xi7jfmlpw9phFZyg4Ah8bxW2Krr53lopuINKHylwf2xNyN8HDTT2lRBX/X/S13MRbAe9 Cl+1RvM4DNB9xzTrxWo3TQfIQ9DF1JClzmwVETc/AjoAVqfW+NJS6oOqlL0Em4+qYYa7 a2g49hQs7d4DVeRcQDWXC4Kaq3wFRKZGIDtUhI5VKBqpLBc48MjwmdLwAP2t5Z6Kvu68 sf/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:content-transfer-encoding:from:mime-version :subject:date:message-id:references:cc:in-reply-to:to; bh=EWJqqy29yofdCquZBPthLER+Jv293+BzSZVb1kweNlE=; b=Oa4aoJrGDMKkErmsTcW1MK7XxNXguFY3fgTR0wOF3x5LOQABNsveDskwliSVg/9qXR aVCSpRFQ/AKDlkwvg1w2GKainmzCCWcMKj8dyzZ92GnOCRychYo/HZMrj9nw/J6bgorQ jJJUO+LylEr6NxWU4hSTTER7bGUjSYo1kd29ltmq4r/2VaaB8cw0WDCpM/hh4ta3yP4t 52PPDElHsh3y2hRVZRUHdBP/hcckBRlRvYaW6fJX1IVLHUQGEbmD0qOwweFVkyGcf/fJ S0K3hh+LojIUdH7XfttZfRsHMcsfE1AHgr5V1yq3Gz8mIggVovMa5RdbRI1ZiMTzO6Uc mDFg== X-Gm-Message-State: APjAAAXHvXWTk6qbSfp62g4l9mDu9675i9clkRFlEgCooZUZdZ4oOD66 fOoaxIu35clgAW+Ka9OcAH37aw== X-Google-Smtp-Source: APXvYqzu7RW2LzgCVPn1UYMRWg4Xv+vumYrColU+r4PBMhJWYci7G8NPsGRGFKpRPd3VwivsJ+cohQ== X-Received: by 2002:a37:b302:: with SMTP id c2mr28515793qkf.442.1570527136679; Tue, 08 Oct 2019 02:32:16 -0700 (PDT) Received: from [192.168.1.183] (pool-71-184-117-43.bstnma.fios.verizon.net. [71.184.117.43]) by smtp.gmail.com with ESMTPSA id d134sm8272302qkg.133.2019.10.08.02.32.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Oct 2019 02:32:15 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v2] mm/page_isolation: fix a deadlock with printk() Date: Tue, 8 Oct 2019 05:32:15 -0400 Message-Id: <43AC5AD1-377D-447C-A703-7F10423E6FA0@lca.pw> References: <20191008081510.ptwmb7zflqiup5py@pathway.suse.cz> Cc: Michal Hocko , sergey.senozhatsky.work@gmail.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, john.ogness@linutronix.de, akpm@linux-foundation.org, david@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <20191008081510.ptwmb7zflqiup5py@pathway.suse.cz> To: Petr Mladek X-Mailer: iPhone Mail (17A860) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > On Oct 8, 2019, at 4:15 AM, Petr Mladek wrote: >=20 > I am curious about CPU2. Does scheduler need to allocate memory? It happens before with debug objects. It might not 100% necessary but it cou= ld easily end up with this way in the current code. Moreover, this is just a= n example of how things could go wrong as it could happen for pi_lock or any= other unknown downstream locks which are not really console related.=