From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751379AbdARROq (ORCPT ); Wed, 18 Jan 2017 12:14:46 -0500 Received: from mga14.intel.com ([192.55.52.115]:38566 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750900AbdARROp (ORCPT ); Wed, 18 Jan 2017 12:14:45 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,249,1477983600"; d="scan'208";a="1084510651" Date: Wed, 18 Jan 2017 20:04:45 +0300 From: "Kirill A. Shutemov" To: Vlastimil Babka Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Aneesh Kumar K . V" , David Rientjes , Andrea Arcangeli Subject: Re: [PATCH] mm/mempolicy.c: do not put mempolicy before using its nodemask Message-ID: <20170118170444.s4z5jqn57fqbnvnf@black.fi.intel.com> References: <20170118141124.8345-1-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170118141124.8345-1-vbabka@suse.cz> User-Agent: NeoMutt/20161126 (1.7.0) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2017 at 03:11:24PM +0100, Vlastimil Babka wrote: > Since commit be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to > alloc_pages_vma") alloc_pages_vma() can potentially free a mempolicy by > mpol_cond_put() before accessing the embedded nodemask by > __alloc_pages_nodemask(). The commit log says it's so "we can use a single > exit path within the function" but that's clearly wrong. We can still do that > when doing mpol_cond_put() after the allocation attempt. > > Make sure the mempolicy is not freed prematurely, otherwise > __alloc_pages_nodemask() can end up using a bogus nodemask, which could lead > e.g. to premature OOM. > > Fixes: be97a41b291e ("mm/mempolicy.c: merge alloc_hugepage_vma to alloc_pages_vma") > Signed-off-by: Vlastimil Babka > Cc: stable@vger.kernel.org > Cc: Aneesh Kumar K.V > Cc: Kirill A. Shutemov > Cc: David Rientjes > Cc: Andrea Arcangeli Looks good to me. Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov