From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965263Ab2I1S7k (ORCPT ); Fri, 28 Sep 2012 14:59:40 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:51579 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965250Ab2I1S7e (ORCPT ); Fri, 28 Sep 2012 14:59:34 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , alan@lxorguk.ukuu.org.uk, =?UTF-8?q?Bj=C3=B8rn=20Mork?= , Ming Lei , Oliver Neukum , "David S. Miller" Subject: =?UTF-8?q?=5B=20116/262=5D=20net=3A=20usbnet=3A=20fix=20softirq=20storm=20on=20suspend?= Date: Fri, 28 Sep 2012 11:50:45 -0700 Message-Id: <20120928183011.841430575@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120928182957.993484211@linuxfoundation.org> References: <20120928182957.993484211@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bjørn Mork commit 85e87870fa18ec9f5df98e2d3b48f3699560a570 upstream. Suspending an open usbnet device results in constant rescheduling of usbnet_bh. commit 65841fd5 "usbnet: handle remote wakeup asap" refactored the usbnet_bh code to allow sharing the urb allocate and submit code with usbnet_resume. In this process, a test for, and immediate return on, ENOLINK from rx_submit was unintentionally dropped. The rx queue will not grow if rx_submit fails, making usbnet_bh reschedule itself. This results in a softirq storm if the error is persistent. rx_submit translates the usb_submit_urb error EHOSTUNREACH into ENOLINK, so this is an expected and persistent error for a suspended device. The old code tested for this condition and avoided rescheduling. Putting this test back. Signed-off-by: Bjørn Mork Cc: Ming Lei Cc: Oliver Neukum Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/usbnet.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1204,19 +1204,26 @@ deferred: } EXPORT_SYMBOL_GPL(usbnet_start_xmit); -static void rx_alloc_submit(struct usbnet *dev, gfp_t flags) +static int rx_alloc_submit(struct usbnet *dev, gfp_t flags) { struct urb *urb; int i; + int ret = 0; /* don't refill the queue all at once */ for (i = 0; i < 10 && dev->rxq.qlen < RX_QLEN(dev); i++) { urb = usb_alloc_urb(0, flags); if (urb != NULL) { - if (rx_submit(dev, urb, flags) == -ENOLINK) - return; + ret = rx_submit(dev, urb, flags); + if (ret) + goto err; + } else { + ret = -ENOMEM; + goto err; } } +err: + return ret; } /*-------------------------------------------------------------------------*/ @@ -1260,7 +1267,8 @@ static void usbnet_bh (unsigned long par int temp = dev->rxq.qlen; if (temp < RX_QLEN(dev)) { - rx_alloc_submit(dev, GFP_ATOMIC); + if (rx_alloc_submit(dev, GFP_ATOMIC) == -ENOLINK) + return; if (temp != dev->rxq.qlen) netif_dbg(dev, link, dev->net, "rxqlen %d --> %d\n",