From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752810AbdARVfA (ORCPT ); Wed, 18 Jan 2017 16:35:00 -0500 Received: from mail-pg0-f46.google.com ([74.125.83.46]:34051 "EHLO mail-pg0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752570AbdARVe6 (ORCPT ); Wed, 18 Jan 2017 16:34:58 -0500 Date: Wed, 18 Jan 2017 13:34:55 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Vlastimil Babka cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, "Aneesh Kumar K . V" , "Kirill A . Shutemov" , Andrea Arcangeli Subject: Re: [PATCH] mm/mempolicy.c: do not put mempolicy before using its nodemask In-Reply-To: <20170118141124.8345-1-vbabka@suse.cz> Message-ID: References: <20170118141124.8345-1-vbabka@suse.cz> User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) 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 On Wed, 18 Jan 2017, 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 Acked-by: David Rientjes I think this deserves Cc: stable@vger.kernel.org [4.0+]