From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756557Ab2K0VIl (ORCPT ); Tue, 27 Nov 2012 16:08:41 -0500 Received: from mga09.intel.com ([134.134.136.24]:27877 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754981Ab2K0VIk (ORCPT ); Tue, 27 Nov 2012 16:08:40 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.84,174,1355126400"; d="scan'208";a="248070105" From: Andi Kleen To: Naoya Horiguchi Cc: Andrew Morton , Tony Luck , Andi Kleen , Wu Fengguang , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm, soft offline: split thp at the beginning of soft_offline_page() References: <1354050331-26844-1-git-send-email-n-horiguchi@ah.jp.nec.com> Date: Tue, 27 Nov 2012 13:08:38 -0800 In-Reply-To: <1354050331-26844-1-git-send-email-n-horiguchi@ah.jp.nec.com> (Naoya Horiguchi's message of "Tue, 27 Nov 2012 16:05:31 -0500") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Naoya Horiguchi writes: > When we try to soft-offline a thp tail page, put_page() is called on the > tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page(). > This patch splits thp before going into the main body of soft-offlining. Looks good. > > The interface of soft-offlining is open for userspace, so this bug can > lead to DoS attack and should be fixed immedately. The interface is root only and root can do everything anyways, so it's not really a security issue. -Andi -- ak@linux.intel.com -- Speaking for myself only