From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: [PATCH] PM / hibernate: Avoid overflow in hibernate_preallocate_memory Date: Tue, 05 Nov 2013 15:16:01 +0800 Message-ID: <52789B31.70005@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mga09.intel.com ([134.134.136.24]:36740 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750774Ab3KEHPQ (ORCPT ); Tue, 5 Nov 2013 02:15:16 -0500 Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Linux-pm mailing list , Leon Drugi 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 | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 98c3b34a4cff..91aa616a1f4e 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1402,7 +1402,8 @@ 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) > pages_highmem ? + (count - max_size - pages_highmem) : 0; pages = preallocate_image_memory(alloc, avail_normal); if (pages < alloc) { /* We have exhausted non-highmem pages, try highmem. */ -- 1.8.4.39.ga0d3f10