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 99792C33CA1 for ; Mon, 20 Jan 2020 07:22:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 654C62077C for ; Mon, 20 Jan 2020 07:22:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 654C62077C 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 037AB6B05B1; Mon, 20 Jan 2020 02:22:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id F2A9E6B05B3; Mon, 20 Jan 2020 02:22:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E415C6B05B4; Mon, 20 Jan 2020 02:22:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0002.hostedemail.com [216.40.44.2]) by kanga.kvack.org (Postfix) with ESMTP id CF71B6B05B1 for ; Mon, 20 Jan 2020 02:22:58 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 8DA8C1CBE for ; Mon, 20 Jan 2020 07:22:58 +0000 (UTC) X-FDA: 76397170836.13.sky36_8e5a6eacdc52e X-HE-Tag: sky36_8e5a6eacdc52e X-Filterd-Recvd-Size: 3271 Received: from mail-wr1-f67.google.com (mail-wr1-f67.google.com [209.85.221.67]) by imf39.hostedemail.com (Postfix) with ESMTP for ; Mon, 20 Jan 2020 07:22:58 +0000 (UTC) Received: by mail-wr1-f67.google.com with SMTP id t2so28332551wrr.1 for ; Sun, 19 Jan 2020 23:22:58 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=XoV6O0m1pCknJULeMQsOZ3LratNUtl8Q4pIJIVCq2CQ=; b=qz7e0cP6nVslGuCx2IbLL5tn0KTehx/3ddHYZGrkUnWGRKQCtiWB079m8vNQ3uFhfZ Ezi3DOCW89dG3rUeXNP6+8dAc0ekB8UDEkfpuEwxgNR1vvyiu3ePuZOkKFbkOO5JczU2 ZUWCZeOh73smjKNewDYldcCmeYTRh+edgFewJjHgmGcrqvQe9oRubxNz6XK0EDM+WzEX W21/uJbDwPYtebI3Td3xuqz+E0fpXR9YV8CtGxaKsow2lY9vWFFwEpkTDom6/z11n7Cu zy1o1Ix5Y5cMUo3kMjYNBjxZNIHWVKjz5tqZHH4+YhTmbNzvwB7OUAPyxUmhDt5BNwH1 Eg9g== X-Gm-Message-State: APjAAAX2SfKp5+Gd+l1uPwZrxOhohGZ2elukzlW0zBObrRGpAvOS+8Bk wXFOvDVX9oZc7u8qH5b2K5k= X-Google-Smtp-Source: APXvYqzywx/yRIN+ucM+OPGKSntfCeJSJma/U31vPXTCEzmOaR/EBCEa8L89Pjw6tvf1P8OKlGk/mw== X-Received: by 2002:adf:fd87:: with SMTP id d7mr17305260wrr.226.1579504977148; Sun, 19 Jan 2020 23:22:57 -0800 (PST) Received: from localhost (ip-37-188-138-155.eurotel.cz. [37.188.138.155]) by smtp.gmail.com with ESMTPSA id g25sm1849534wmh.3.2020.01.19.23.22.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Jan 2020 23:22:56 -0800 (PST) Date: Mon, 20 Jan 2020 08:22:55 +0100 From: Michal Hocko To: Qian Cai Cc: David Hildenbrand , akpm@linux-foundation.org, sergey.senozhatsky.work@gmail.com, pmladek@suse.com, rostedt@goodmis.org, peterz@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next v5] mm/hotplug: silence a lockdep splat with printk() Message-ID: <20200120072255.GB18451@dhcp22.suse.cz> References: <5abf5440-7c1c-b9e9-9770-b89759771a44@redhat.com> <587CD165-FAA4-4369-9F30-CB8F9C03F062@lca.pw> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <587CD165-FAA4-4369-9F30-CB8F9C03F062@lca.pw> User-Agent: Mutt/1.12.2 (2019-09-21) X-Bogosity: Ham, tests=bogofilter, spamicity=0.067523, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri 17-01-20 11:35:08, Qian Cai wrote: > > > > On Jan 17, 2020, at 11:27 AM, David Hildenbrand wrote: > > > > the "int" should go onto the next line as well > > [...] > > Yes. > > > apart from that looks good to me. I hope we won't have a whac-a-mole > > with printk() (including WARN_ON() etc?) under the zone lock. This all > > screams for a better fix. > > WARN_ON() is normally not a concern. Once it happens here, we will > figure out the reason why it happens in the first place and shut it > off there instead. It is very much the same concern as any other printk which might deadlock. It is true this is WARN_ONCE so the likelyhood is much smaller. But you know, probability is not going to help you if you are unlucky ;) -- Michal Hocko SUSE Labs