Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752214AbbGWLj4 (ORCPT ); Thu, 23 Jul 2015 07:39:56 -0400 Received: from collab.rosalab.ru ([195.19.76.181]:48679 "EHLO collab.rosalab.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751025AbbGWLjq (ORCPT ); Thu, 23 Jul 2015 07:39:46 -0400 Subject: Re: Several races in "usbnet" module (kernel 4.1.x) To: Oliver Neukum References: <55AD3A41.2040100@rosalab.ru> <1437644594.4377.12.camel@suse.com> Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org, LKML From: Eugene Shatokhin Organization: ROSA Message-ID: <55B0D27E.8090701@rosalab.ru> Date: Thu, 23 Jul 2015 14:39:42 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: <1437644594.4377.12.camel@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1013 Lines: 33 23.07.2015 12:43, Oliver Neukum пишет: > On Mon, 2015-07-20 at 21:13 +0300, Eugene Shatokhin wrote: >> [Race #5] >> >> Race on dev->rx_urb_size. I reproduced it a similar way as the races >> #2 >> and #3 (changing MTU while downloading files). >> >> dev->rx_urb_size is written to here: >> #0 usbnet_change_mtu (usbnet.c:392) >> dev->rx_urb_size = dev->hard_mtu; >> >> Here is the conflicting read from dev->rx_urb_size: >> * rx_submit (usbnet.c:467) >> size_t size = dev->rx_urb_size; > > Yes, but what is the actual bad race? I mean, if you change > the MTU in operation, there will be a race. That is just > unavoidable. > Do we generate errors? No, I have observed no problems due to this race so far. Regards, Eugene -- 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/