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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 BD9A4C31E5E for ; Tue, 18 Jun 2019 20:02:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95C9E20679 for ; Tue, 18 Jun 2019 20:02:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="D4LqXjau" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730467AbfFRUC6 (ORCPT ); Tue, 18 Jun 2019 16:02:58 -0400 Received: from mail-lf1-f65.google.com ([209.85.167.65]:39781 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730189AbfFRUC5 (ORCPT ); Tue, 18 Jun 2019 16:02:57 -0400 Received: by mail-lf1-f65.google.com with SMTP id p24so10253573lfo.6; Tue, 18 Jun 2019 13:02:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=cVl3SIklS0nHd797FYY4cxHoZEAnPslNYDQOv5OhMDM=; b=D4LqXjauq6e8L92SXdCI8dBOeZ9g3qnR+MvRfoDQP4UPl32roBpvGWprF3TjlmHSja eZ/6/ZjWzgRN9htttHJTrPzVJCoFvbIqpDA3vC1Cl8utSLu6XzXuxp7AabXcEV/Om6He yHiGKcbb2hB4xqghyhAsPiwk4UDzPPVak57pe2KgOS495X1pgno1vQnCtMEqE80s7SDd b/xHq26uOBUeyQq+iykM4OWAPJ5VZU59856GZ2QUrHkBfHjmAmn1pe6xmy0ce97q8t4y IfDjJ3INQeQbB5asZ/xxIwCfBifBBZjV8Yfyh2WDBB5G9dWZfMSeieDwA07Xq9c2du8P K49g== 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; bh=cVl3SIklS0nHd797FYY4cxHoZEAnPslNYDQOv5OhMDM=; b=L+Mw5H2tzDvLIImNk+lqFdo/mYtJN4BEMzCzzEVGODbbeSfr7IGM+GLypvYdOAa6h/ Q1aoHhe40DvtMx2y5e9xNQb2TQ8T2ktYrDABU6RVhk+DZfGluuE1fMH+7mK0wDjpiXmE YJEdUTXMTwZKmbRxtrF5Qj54ZlEjaXd4roWCtbN1slPBmX2Y6x8bk2VOIYjp94Zf1hxY qBTwk50bQ3WKs0vdaXU6UDYuNp8PjibeZ3eM4s21gEu5f1aW8g3X/p9iTwGOw85OloTN 2XEhzpgUaBT7Q13MJ8XF91p8RQ1SDeZ3HMKYiwAX73D3huBEdcLePjTffCkD/VAols+b exSQ== X-Gm-Message-State: APjAAAVxactIGjKsD2BvM0z4i+IPMcbVsUSG7HWws/7qqjpGNpfhMg3a +bHSEg8wR1KH8veoIB64IqksEHY3BDA= X-Google-Smtp-Source: APXvYqzKO9zG2G36ym9WsDHSLpShB5YrpwSynDJM7DvNbZeZWMwp4g4634Uhi3PMXIvAfLocbMbxAg== X-Received: by 2002:a05:6512:29a:: with SMTP id j26mr26109062lfp.44.1560888175432; Tue, 18 Jun 2019 13:02:55 -0700 (PDT) Received: from esperanza ([176.120.239.149]) by smtp.gmail.com with ESMTPSA id j23sm1621386lfb.93.2019.06.18.13.02.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 18 Jun 2019 13:02:54 -0700 (PDT) Date: Tue, 18 Jun 2019 23:02:51 +0300 From: Vladimir Davydov To: Andrew Morton Cc: Colin King , Michal Hocko , Mike Rapoport , Mel Gorman , Stephen Rothwell , Andrey Ryabinin , linux-mm@kvack.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: idle-page: fix oops because end_pfn is larger than max_pfn Message-ID: <20190618200251.hd2uk6qzyvsy55py@esperanza> References: <20190618124352.28307-1-colin.king@canonical.com> <20190618124502.7b9c32a00a54f0c618a12ca4@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190618124502.7b9c32a00a54f0c618a12ca4@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 18, 2019 at 12:45:02PM -0700, Andrew Morton wrote: > On Tue, 18 Jun 2019 13:43:52 +0100 Colin King wrote: > > > From: Colin Ian King > > > > Currently the calcuation of end_pfn can round up the pfn number to > > more than the actual maximum number of pfns, causing an Oops. Fix > > this by ensuring end_pfn is never more than max_pfn. > > > > This can be easily triggered when on systems where the end_pfn gets > > rounded up to more than max_pfn using the idle-page stress-ng > > stress test: > > > > cc Vladimir. This seems rather obvious - I'm wondering if the code was > that way for some subtle reason? No subtle reason at all - just a bug. The patch looks good to me, Acked-by: Vladimir Davydov