From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759808Ab3LFXWc (ORCPT ); Fri, 6 Dec 2013 18:22:32 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:49069 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423069Ab3LFXVB (ORCPT ); Fri, 6 Dec 2013 18:21:01 -0500 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Aaron Lu , "Rafael J. Wysocki" , Kamal Mostafa Subject: [PATCH 3.8 065/152] PM / hibernate: Avoid overflow in hibernate_preallocate_memory() Date: Fri, 6 Dec 2013 15:09:49 -0800 Message-Id: <1386371476-2477-66-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.3.2 In-Reply-To: <1386371476-2477-1-git-send-email-kamal@canonical.com> References: <1386371476-2477-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.8.13.14 -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: Kamal Mostafa --- 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 0de2857..91c04f1 100644 --- 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. */ -- 1.8.3.2