From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750703AbWH3Iky (ORCPT ); Wed, 30 Aug 2006 04:40:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750702AbWH3Iky (ORCPT ); Wed, 30 Aug 2006 04:40:54 -0400 Received: from www.osadl.org ([213.239.205.134]:47021 "EHLO mail.tglx.de") by vger.kernel.org with ESMTP id S1750703AbWH3Ikx (ORCPT ); Wed, 30 Aug 2006 04:40:53 -0400 Subject: [PATCH] prevent timespec/timeval to ktime_t overflow From: Thomas Gleixner Reply-To: tglx@linutronix.de To: Andrew Morton Cc: Ingo Molnar , LKML , Frank v Waveren Content-Type: text/plain Date: Wed, 30 Aug 2006 10:44:28 +0200 Message-Id: <1156927468.29250.113.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Frank v. Waveren pointed out that on 64bit machines the timespec to ktime_t conversion might overflow. This is also true for timeval to ktime_t conversions. This breaks a "sleep inf" on 64bit machines. While a timespec/timeval with tx.sec = MAX_LONG is valid by specification the internal representation of ktime_t is based on nanoseconds. The conversion of seconds to nanoseconds overflows for seconds values >= (MAX_LONG / NSEC_PER_SEC). Check the seconds argument to the conversion and limit it to the maximum time which can be represented by ktime_t. Signed-off-by: Thomas Gleixner diff --git a/include/linux/ktime.h b/include/linux/ktime.h index ed3396d..1beafb3 100644 --- a/include/linux/ktime.h +++ b/include/linux/ktime.h @@ -57,6 +57,7 @@ typedef union { } ktime_t; #define KTIME_MAX (~((u64)1 << 63)) +#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) /* * ktime_t definitions when using the 64-bit scalar representation: @@ -73,6 +74,10 @@ typedef union { */ static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) { +#if (BITS_PER_LONG == 64) + if (unlikely(secs >= KTIME_SEC_MAX)) + return (ktime_t){ .tv64 = KTIME_MAX }; +#endif return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs }; }