From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932390AbaFJU3O (ORCPT ); Tue, 10 Jun 2014 16:29:14 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:35054 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753911AbaFJTsv (ORCPT ); Tue, 10 Jun 2014 15:48:51 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Jiri Bohac , Thomas Gleixner , Kamal Mostafa Subject: [PATCH 3.13 120/160] timer: Prevent overflow in apply_slack Date: Tue, 10 Jun 2014 12:46:00 -0700 Message-Id: <1402429600-20477-121-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1402429600-20477-1-git-send-email-kamal@canonical.com> References: <1402429600-20477-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.13.11.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Bohac commit 98a01e779f3c66b0b11cd7e64d531c0e41c95762 upstream. On architectures with sizeof(int) < sizeof (long), the computation of mask inside apply_slack() can be undefined if the computed bit is > 32. E.g. with: expires = 0xffffe6f5 and slack = 25, we get: expires_limit = 0x20000000e bit = 33 mask = (1 << 33) - 1 /* undefined */ On x86, mask becomes 1 and and the slack is not applied properly. On s390, mask is -1, expires is set to 0 and the timer fires immediately. Use 1UL << bit to solve that issue. Suggested-by: Deborah Townsend Signed-off-by: Jiri Bohac Link: http://lkml.kernel.org/r/20140418152310.GA13654@midget.suse.cz Signed-off-by: Thomas Gleixner Signed-off-by: Kamal Mostafa --- kernel/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/timer.c b/kernel/timer.c index accfd24..38f0d40 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -822,7 +822,7 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires) bit = find_last_bit(&mask, BITS_PER_LONG); - mask = (1 << bit) - 1; + mask = (1UL << bit) - 1; expires_limit = expires_limit & ~(mask); -- 1.9.1