From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754754AbaFEFJZ (ORCPT ); Thu, 5 Jun 2014 01:09:25 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43752 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752251AbaFEEUQ (ORCPT ); Thu, 5 Jun 2014 00:20:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Deborah Townsend , Jiri Bohac , Thomas Gleixner Subject: [PATCH 3.4 039/214] timer: Prevent overflow in apply_slack Date: Wed, 4 Jun 2014 21:16:42 -0700 Message-Id: <20140605041644.947108437@linuxfoundation.org> X-Mailer: git-send-email 2.0.0 In-Reply-To: <20140605041639.638675216@linuxfoundation.org> References: <20140605041639.638675216@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-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: Greg Kroah-Hartman --- kernel/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/timer.c +++ b/kernel/timer.c @@ -815,7 +815,7 @@ unsigned long apply_slack(struct timer_l bit = find_last_bit(&mask, BITS_PER_LONG); - mask = (1 << bit) - 1; + mask = (1UL << bit) - 1; expires_limit = expires_limit & ~(mask);