From patchwork Wed Nov 6 00:41:31 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aaron Lu X-Patchwork-Id: 3144461 Return-Path: X-Original-To: patchwork-linux-pm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id E2F6E9F3C4 for ; Wed, 6 Nov 2013 00:40:53 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D73D920616 for ; Wed, 6 Nov 2013 00:40:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B3BA4205AC for ; Wed, 6 Nov 2013 00:40:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755558Ab3KFAkr (ORCPT ); Tue, 5 Nov 2013 19:40:47 -0500 Received: from mga09.intel.com ([134.134.136.24]:52711 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755373Ab3KFAkr (ORCPT ); Tue, 5 Nov 2013 19:40:47 -0500 Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP; 05 Nov 2013 16:37:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.93,535,1378882800"; d="scan'208";a="404204198" Received: from aaronlu.sh.intel.com ([10.239.37.146]) by orsmga001.jf.intel.com with ESMTP; 05 Nov 2013 16:40:45 -0800 Message-ID: <5279903B.40202@intel.com> Date: Wed, 06 Nov 2013 08:41:31 +0800 From: Aaron Lu Organization: Intel, Shanghai, PRC MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Linux-pm mailing list , Leon Drugi Subject: [PATCH update] PM / hibernate: Avoid overflow in hibernate_preallocate_memory References: <52789B31.70005@intel.com> <1974778.1p97Y6DIEX@vostro.rjw.lan> In-Reply-To: <1974778.1p97Y6DIEX@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On 11/05/2013 10:22 PM, Rafael J. Wysocki wrote: > On Tuesday, November 05, 2013 03:16:01 PM Aaron Lu wrote: >> pages_highmem = preallocate_image_highmem(highmem / 2); >> - alloc = (count - max_size) - pages_highmem; >> + alloc = (count - max_size) > pages_highmem ? >> + (count - max_size - pages_highmem) : 0; > > Well, what about > > alloc = count - max_size; > if (alloc > pages_highmem) > alloc -= pages_highmem; > else > alloc = 0; > OK, here it comes: From: Aaron Lu Subject: [PATCH] PM / hibernate: Avoid overflow in hibernate_preallocate_memory When system has a lot of highmem(e.g. 16GiB using a 32 bits kernel), the code to calculate how much memory we need to preallocate in normal zone may cause overflow. As Leon has analysed: " It looks that during computing 'alloc' variable there is overflow: alloc = (3943404 - 1970542) - 1978280 = -5418 (signed) And this function goes to err_out. " Fix this by avoiding that overflow. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=60817 Reported-and-tested-by: Leon Drugi Cc: stable Signed-off-by: Aaron Lu --- kernel/power/snapshot.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 98c3b34a4cff..10c22cae83a0 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1402,7 +1402,11 @@ int hibernate_preallocate_memory(void) * highmem and non-highmem zones separately. */ pages_highmem = preallocate_image_highmem(highmem / 2); - alloc = (count - max_size) - pages_highmem; + alloc = count - max_size; + if (alloc > pages_highmem) + alloc -= pages_highmem; + else + alloc = 0; pages = preallocate_image_memory(alloc, avail_normal); if (pages < alloc) { /* We have exhausted non-highmem pages, try highmem. */