From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758811Ab3LBU7S (ORCPT ); Mon, 2 Dec 2013 15:59:18 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:38475 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754092Ab3LBTNf (ORCPT ); Mon, 2 Dec 2013 14:13:35 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Aaron Lu , "Rafael J. Wysocki" Subject: [PATCH 3.10 076/173] PM / hibernate: Avoid overflow in hibernate_preallocate_memory() Date: Mon, 2 Dec 2013 11:10:59 -0800 Message-Id: <20131202191152.058754452@linuxfoundation.org> X-Mailer: git-send-email 1.8.4.3.gca3854a In-Reply-To: <20131202191142.873808297@linuxfoundation.org> References: <20131202191142.873808297@linuxfoundation.org> User-Agent: quilt/0.60-8.1.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Aaron Lu commit fd432b9f8c7c88428a4635b9f5a9c6e174df6e36 upstream. 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. References: https://bugzilla.kernel.org/show_bug.cgi?id=60817 Reported-and-tested-by: Leon Drugi Signed-off-by: Aaron Lu Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- kernel/power/snapshot.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1398,7 +1398,11 @@ 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. */