From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754886Ab3G2F7q (ORCPT ); Mon, 29 Jul 2013 01:59:46 -0400 Received: from guitar.tcltek.co.il ([192.115.133.116]:54782 "EHLO sivan.tkos.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752864Ab3G2F7p (ORCPT ); Mon, 29 Jul 2013 01:59:45 -0400 Date: Mon, 29 Jul 2013 08:59:39 +0300 From: Baruch Siach To: John Stultz , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-xtensa@linux-xtensa.org Subject: Re: [PATCH] time: sched_clock: fix integer overflow Message-ID: <20130729055939.GK5161@tarshish> References: <232c026d1b8d2556679aea56cf77a6811f9a96c5.1374054369.git.baruch@tkos.co.il> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <232c026d1b8d2556679aea56cf77a6811f9a96c5.1374054369.git.baruch@tkos.co.il> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Thomas, John, On Wed, Jul 17, 2013 at 12:46:53PM +0300, Baruch Siach wrote: > The expression '(1 << 32)' happens to evaluate as 0 on ARM, but it evaluates as > 1 on xtensa and x86_64. This zeros sched_clock_mask, and breaks sched_clock(). > Set the type of 1 to 'unsigned long long' to get the value we need. Ping? -rc3 is out, and this bug (which currently breaks xtensa) is not fixed yet. Please consider applying. baruch > Reported-by: Max Filippov > Tested-by: Max Filippov > Acked-by: Russell King > Signed-off-by: Baruch Siach > --- > kernel/time/sched_clock.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c > index a326f27..0b479a6 100644 > --- a/kernel/time/sched_clock.c > +++ b/kernel/time/sched_clock.c > @@ -121,7 +121,7 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate) > BUG_ON(bits > 32); > WARN_ON(!irqs_disabled()); > read_sched_clock = read; > - sched_clock_mask = (1 << bits) - 1; > + sched_clock_mask = (1ULL << bits) - 1; > cd.rate = rate; > > /* calculate the mult/shift to convert counter ticks to ns. */ > -- -- http://baruch.siach.name/blog/ ~. .~ Tk Open Systems =}------------------------------------------------ooO--U--Ooo------------{= - baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -