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=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 72ED4C4360C for ; Tue, 8 Oct 2019 12:00:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 485F420815 for ; Tue, 8 Oct 2019 12:00:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lca.pw header.i=@lca.pw header.b="FB3bYM5H" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730835AbfJHMAp (ORCPT ); Tue, 8 Oct 2019 08:00:45 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:42666 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730671AbfJHMAp (ORCPT ); Tue, 8 Oct 2019 08:00:45 -0400 Received: by mail-qt1-f196.google.com with SMTP id w14so24779257qto.9 for ; Tue, 08 Oct 2019 05:00:44 -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=hMT2QOE/OAMarN+nxsAfhwGq8004d2eHigWLvE3NWsY=; b=FB3bYM5H6/0Vu2sXyCUS3ZXh6QnbHGNFksz2EMZQEQv1hYOCRU5i24RNJeiaYvvqDa j5mMRmFbRHTLXXcQ8oqs0e/akRMyHw3ZKTQkzQJ6L4GbfwasRzDMC7xA79pZ0Bis9fnW yOflSlbJwdY6Nr3iBQ+AvydqTfY5CzUTRm5D2MGUAUjCGtzgrXz+Dc0vJaJbqP2xq56I fTGqKFxvtOhGZV+4k+RzL12Xg6fRet2FxCe4Jm8Q+UAe4UinOEz0axC0DW9XXaO5+wtt eDs9bhFHEtuabXlmBH5vl+rP/h2++WUxQTrMpgwBWazTVr/nw6Xg5chm1q0q1cZO/vrT wzLQ== 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=hMT2QOE/OAMarN+nxsAfhwGq8004d2eHigWLvE3NWsY=; b=g9oFC+DQ8nL4F1ayIRxZbE2RUlHEMgeqwh2eLSAQgZJ25z0RvO63QZpVhGJjA5JpTN ZnO5oNiV5lKqcL9XDG0djX5YO7LPZ3qekGL7iDK06VYctv32TRlgybF+KNyjIwJdueNT qOIeHk24HUCi702ra0w4mwwwC6iZiVFr+KDQ+xvlsQ+M8RIE7uiHdw+qccH9h2Vec73b PUy5Gi/g8r9XYEMjJoU2ne5Y1NxhMv7kAZBTQZdBpEeGWWgZf2kxDyjpPO9+pJOX4r85 8w7a2IObEeguO4HZdBdqsL4CQqzD7XfYOc5fLQnBaneCBQyBD3DtGTB/94ww1V21VooT B+fw== X-Gm-Message-State: APjAAAVqvRYOLfh4wDxudqdIFbX88CthRM0xIkIs1dLhM5Z3EGRxBA4a u1M5iJrlR3MaZ0in54+v/abDYQ== X-Google-Smtp-Source: APXvYqwi6mpb3TUaZFLEjiraqYM9798ysDR+1/i/r66aOzL4Y0x9nk3+sxOjsGTBD5LGyNEJt0PS6A== X-Received: by 2002:aed:2d67:: with SMTP id h94mr34903151qtd.63.1570536044299; Tue, 08 Oct 2019 05:00:44 -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 i25sm6765898qkk.30.2019.10.08.05.00.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Oct 2019 05:00:43 -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 08:00:43 -0400 Message-Id: <3836DE34-9DD2-4815-9E1E-CB87D881B9AD@lca.pw> References: <20191008103907.GE6681@dhcp22.suse.cz> Cc: Petr Mladek , 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 In-Reply-To: <20191008103907.GE6681@dhcp22.suse.cz> To: Michal Hocko X-Mailer: iPhone Mail (17A860) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Oct 8, 2019, at 6:39 AM, Michal Hocko wrote: >=20 > Have you actually triggered any real deadlock? With a zone->lock in > place it would be pretty clear with hard lockups detected. Yes, I did trigger here and there, and those lockdep splats are especially u= seful to figure out why.=