From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758704AbYKQHfs (ORCPT ); Mon, 17 Nov 2008 02:35:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752546AbYKQHVo (ORCPT ); Mon, 17 Nov 2008 02:21:44 -0500 Received: from kroah.org ([198.145.64.141]:38690 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755595AbYKQHVh (ORCPT ); Mon, 17 Nov 2008 02:21:37 -0500 Date: Sun, 16 Nov 2008 23:16:55 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Alan Stern , David Brownell , Greg Kroah-Hartman Subject: [patch 39/46] USB: EHCI: fix divide-by-zero bug Message-ID: <20081117071655.GN29522@kroah.com> References: <20081117070621.430169021@blue.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="usb-ehci-fix-divide-by-zero-bug.patch" In-Reply-To: <20081117071333.GA29522@kroah.com> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27-stable review patch. If anyone has any objections, please let us know. ------------------ From: Alan Stern commit 372dd6e8ed924e876f3beb598721e813ad7fa323 upstream. This patch (as1164) fixes a bug in the EHCI scheduler. The interval value it uses is already in linear format, not logarithmically coded. The existing code can sometimes crash the system by trying to divide by zero. Signed-off-by: Alan Stern Cc: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-sched.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -918,7 +918,7 @@ iso_stream_init ( */ stream->usecs = HS_USECS_ISO (maxp); bandwidth = stream->usecs * 8; - bandwidth /= 1 << (interval - 1); + bandwidth /= interval; } else { u32 addr; @@ -951,7 +951,7 @@ iso_stream_init ( } else stream->raw_mask = smask_out [hs_transfers - 1]; bandwidth = stream->usecs + stream->c_usecs; - bandwidth /= 1 << (interval + 2); + bandwidth /= interval << 3; /* stream->splits gets created from raw_mask later */ stream->address = cpu_to_hc32(ehci, addr); --