Received: by 2002:a25:683:0:0:0:0:0 with SMTP id 125csp4153854ybg; Sun, 7 Jun 2020 23:53:43 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyfRxNZN5W+bURcmtHGGMleFTZEIjMBg3VnhCrSUUY8Oschr2G817S+jD7vtB3QBaO8VkxG X-Received: by 2002:a05:6402:1812:: with SMTP id g18mr20279381edy.96.1591599222898; Sun, 07 Jun 2020 23:53:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1591599222; cv=none; d=google.com; s=arc-20160816; b=vGMtGjivUPb22YxnKjspJ7rYBYF48M2azaajhYXEUuUlqEhHsnh6R3HpytuKyeDsaL tTa7ftL1IYYTlwB7CVJUK+CEefm5+cqzvthdwriyUvNhzU65HlJhmvW/2MR8m9B+ch+N rp4rnDX08pJdIhxZy1Hhh0qfpJgYumyPvi08Kk/GjrAeChTc5kV4/QVnwIvUKnvFu/OX 7lc3ekQFZtJ4Q7zGYtIheF8m6hTpMu5uQUAtI+sfaBpNuQlKNvJixr5TWbvrQ26GVE43 Qj098P/7JxDaHNcQGDTWtwwXC+2Ne9d9VQNjtbdGvy2Ka4zv8dDTldqgrpuGLToVMPXd h9og== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date; bh=bJC+aZPQCkED1xiIc6hzWH+C38sgTuBF5bxvWa5Jw60=; b=NiVwlaAjwJA5P8dLMoqEiIyH7AaVhWI2ARNV4Dm02Gs0fanG7f/vBZcdEogNv2MrEj Bq5yMUJG14G4Qc2BuH3x3yA0OCj3+xaqQJvYgi6r0ERVftE92UclnCO8VOTycYtha8rY kqPtHT6iJliNQ9sBpo8sXtQV8seA21mvb6iKY/E7w38KwJnyOYEy0USgeARIeou1MqE0 rDDcSDBnyFjMvP8J1gstPe1aoxTdx+H+K6mCdom1ap8B3vKPG5Cu2wVALIpZ0GC6gzCU ZFWxK3kAwiGwEDq9i1EpbZLMbbjcMlulP4gyaybGxEkdhKxJp4oRP0jtf9bJw0j0Kacb spIA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id cm13si7941295edb.246.2020.06.07.23.53.19; Sun, 07 Jun 2020 23:53:42 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728953AbgFHGvY (ORCPT + 99 others); Mon, 8 Jun 2020 02:51:24 -0400 Received: from verein.lst.de ([213.95.11.211]:36063 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728334AbgFHGvX (ORCPT ); Mon, 8 Jun 2020 02:51:23 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 1AB7368AFE; Mon, 8 Jun 2020 08:51:20 +0200 (CEST) Date: Mon, 8 Jun 2020 08:51:20 +0200 From: Christoph Hellwig To: Vegard Nossum Cc: Christoph Hellwig , Kees Cook , Iurii Zaikin , Alexei Starovoitov , Daniel Borkmann , linux-kernel@vger.kernel.org, Al Viro , bpf@vger.kernel.org, Andrey Ignatov Subject: Re: WARNING: CPU: 1 PID: 52 at mm/page_alloc.c:4826 __alloc_pages_nodemask (Re: [PATCH 5/5] sysctl: pass kernel pointers to ->proc_handler) Message-ID: <20200608065120.GA17859@lst.de> References: <20200424064338.538313-1-hch@lst.de> <20200424064338.538313-6-hch@lst.de> <1fc7ce08-26a7-59ff-e580-4e6c22554752@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1fc7ce08-26a7-59ff-e580-4e6c22554752@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 04, 2020 at 10:22:21PM +0200, Vegard Nossum wrote: > It's easy to reproduce by just doing > > read(open("/proc/sys/vm/swappiness", O_RDONLY), 0, 512UL * 1024 * 1024 > * 1024); > > or so. Reverting the commit fixes the issue for me. Yes, doing giant allocations will fail and trace. We have to options here that both seems sensible: - trunate sysctrl calls to some sensible length - (optionally) use vmalloc Is this a real application or just a test case trying to do the stupidmost possible thing?