Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964843AbaD3Lsy (ORCPT ); Wed, 30 Apr 2014 07:48:54 -0400 Received: from terminus.zytor.com ([198.137.202.10]:48854 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758496AbaD3Lsx (ORCPT ); Wed, 30 Apr 2014 07:48:53 -0400 Date: Wed, 30 Apr 2014 04:48:31 -0700 From: tip-bot for Jiri Bohac Message-ID: Cc: linux-kernel@vger.kernel.org, dstownse@us.ibm.com, hpa@zytor.com, mingo@kernel.org, jbohac@suse.cz, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, dstownse@us.ibm.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, jbohac@suse.cz In-Reply-To: <20140418152310.GA13654@midget.suse.cz> References: <20140418152310.GA13654@midget.suse.cz> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] timer: Prevent overflow in apply_slack Git-Commit-ID: 98a01e779f3c66b0b11cd7e64d531c0e41c95762 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 98a01e779f3c66b0b11cd7e64d531c0e41c95762 Gitweb: http://git.kernel.org/tip/98a01e779f3c66b0b11cd7e64d531c0e41c95762 Author: Jiri Bohac AuthorDate: Fri, 18 Apr 2014 17:23:11 +0200 Committer: Thomas Gleixner CommitDate: Wed, 30 Apr 2014 13:46:17 +0200 timer: Prevent overflow in apply_slack 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 Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20140418152310.GA13654@midget.suse.cz Signed-off-by: Thomas Gleixner --- kernel/timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/timer.c b/kernel/timer.c index 87bd529..3bb01a3 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -838,7 +838,7 @@ 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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/