Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754523Ab3HERxT (ORCPT ); Mon, 5 Aug 2013 13:53:19 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:38030 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754497Ab3HERxQ (ORCPT ); Mon, 5 Aug 2013 13:53:16 -0400 Date: Mon, 5 Aug 2013 20:53:02 +0300 From: Dan Carpenter To: Rupesh Gujare Cc: devel@linuxdriverproject.org, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] staging: ozwpan: Increment port number for new device. Message-ID: <20130805175302.GJ5051@mwanda> References: <1375724415-10801-1-git-send-email-rupesh.gujare@atmel.com> <1375724415-10801-3-git-send-email-rupesh.gujare@atmel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375724415-10801-3-git-send-email-rupesh.gujare@atmel.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1093 Lines: 29 On Mon, Aug 05, 2013 at 06:40:13PM +0100, Rupesh Gujare wrote: > This patch fixes crash issue when there is quick cycle of > de-enumeration & enumeration due to loss of wireless link. > > It is found that sometimes new device (or coming back device) > returns very fast, even before USB core read out hub status, > resulting in allocation of same port, which results in unstable > system & crash. > > Above issue is resolved by making sure that we always assign > new port to new device, making sure that USB core reads correct > hub status. > This feels like papering over the problem. Surely the real fix would be to improve the reference counting. This patch is probably effective but it makes the code more subtle and it shows that we don't really understand what we are doing with regards to reference counting. regards, dan carpenter -- 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/