Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S942508AbdDTGyh (ORCPT ); Thu, 20 Apr 2017 02:54:37 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:47038 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966900AbdDTGkE (ORCPT ); Thu, 20 Apr 2017 02:40:04 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vitaly Kuznetsov , "K. Y. Srinivasan" Subject: [PATCH 3.18 032/124] Drivers: hv: balloon: dont crash when memory is added in non-sorted order Date: Thu, 20 Apr 2017 08:35:07 +0200 Message-Id: <20170420063558.278454375@linuxfoundation.org> X-Mailer: git-send-email 2.12.2 In-Reply-To: <20170420063557.021306233@linuxfoundation.org> References: <20170420063557.021306233@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1703 Lines: 46 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vitaly Kuznetsov commit 77c0c9735bc0ba5898e637a3a20d6bcb50e3f67d upstream. When we iterate through all HA regions in handle_pg_range() we have an assumption that all these regions are sorted in the list and the 'start_pfn >= has->end_pfn' check is enough to find the proper region. Unfortunately it's not the case with WS2016 where host can hot-add regions in a different order. We end up modifying the wrong HA region and crashing later on pages online. Modify the check to make sure we found the region we were searching for while iterating. Fix the same check in pfn_covered() as well. Signed-off-by: Vitaly Kuznetsov Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/hv_balloon.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/hv/hv_balloon.c +++ b/drivers/hv/hv_balloon.c @@ -673,7 +673,7 @@ static bool pfn_covered(unsigned long st * If the pfn range we are dealing with is not in the current * "hot add block", move on. */ - if ((start_pfn >= has->end_pfn)) + if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) continue; /* * If the current hot add-request extends beyond @@ -728,7 +728,7 @@ static unsigned long handle_pg_range(uns * If the pfn range we are dealing with is not in the current * "hot add block", move on. */ - if ((start_pfn >= has->end_pfn)) + if (start_pfn < has->start_pfn || start_pfn >= has->end_pfn) continue; old_covered_state = has->covered_end_pfn;