From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Mack Subject: Re: question about drivers/net/ethernet/ti/cpsw.c Date: Tue, 02 Sep 2014 11:34:16 +0200 Message-ID: <54058F18.8060709@gmail.com> References: <20140901.181101.2132157946809255487.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Cc: netdev@vger.kernel.org To: David Miller , julia.lawall@lip6.fr Return-path: Received: from mail-we0-f172.google.com ([74.125.82.172]:46145 "EHLO mail-we0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752076AbaIBJeT (ORCPT ); Tue, 2 Sep 2014 05:34:19 -0400 Received: by mail-we0-f172.google.com with SMTP id q59so6677720wes.3 for ; Tue, 02 Sep 2014 02:34:18 -0700 (PDT) In-Reply-To: <20140901.181101.2132157946809255487.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 09/02/2014 03:11 AM, David Miller wrote: > From: Julia Lawall > Date: Thu, 28 Aug 2014 21:26:55 +0200 (CEST) > >> I wonder if the following patch: >> >> commit aa1a15e2d9199711cdcc9399fdb22544ab835a83 >> Author: Daniel Mack >> Date: Sat Sep 21 00:50:38 2013 +0530 >> >> introduced a race condition in drivers/net/ethernet/ti/cpsw.c. I was >> looking at an old version of the file (Linux 3.10), and it has >> >> clean_irq_ret: >> for (i = 0; i < priv->num_irqs; i++) >> free_irq(priv->irqs_table[i], priv); >> >> at the beginning of the cleanup code of the probe function (cpsw_probe). >> The above patch replaces request_irq by devm_request_irq and gets rid of >> the above cleanup code. But that moves the stopping of the interrupts >> after the following code at the end of the function: >> >> free_netdev(priv->ndev); >> >> The interrupt handler (cpsw_interrupt) does reference priv->ndev: >> >> if (netif_running(priv->ndev)) { >> napi_schedule(&priv->napi); >> return IRQ_HANDLED; >> } >> >> so perhaps this could be a problem. The same happens in the remove >> function. > > It could definitely be a problem. > > Probably it would be better for this device to request IRQs in open > and release them in close like so many other networking drivers do. Thanks for spotting this, Julia! I'll be working on a fix for this as soon as I can. Best regards, Daniel