From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hector Palacios Subject: infinite spin in RT when booting with DHCP on Date: Wed, 01 Feb 2012 13:28:16 +0100 Message-ID: <4F292FE0.7090302@digi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: lclaudio@uudg.org, rostedt@goodmis.org, efault@gmx.de To: linux-rt-users@vger.kernel.org Return-path: Received: from plane.gmane.org ([80.91.229.3]:33758 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753349Ab2BAMfL (ORCPT ); Wed, 1 Feb 2012 07:35:11 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1RsZOx-0001Bu-I3 for linux-rt-users@vger.kernel.org; Wed, 01 Feb 2012 13:35:03 +0100 Received: from 217.151.242.14 ([217.151.242.14]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 01 Feb 2012 13:35:03 +0100 Received: from hector.palacios by 217.151.242.14 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 01 Feb 2012 13:35:03 +0100 Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hello, I'm working on a 2.6.31.14 kernel on ARM where I applied the RT PREEMPT= patch=20 2.6.31.12-rt21. When booting my platform with DHCP on, the DHCP request is sent by the = network driver=20 before the PHY has even started the autonegotiation. Since the PHY is not ready, the TX interrupt returns with NETDEV_TX_BUS= Y but the=20 softirq [sirq-net-tx] seems to have entered an infinite spin, as my sys= tem is=20 practically hung and 'top' reveals [sirq-net-tx/0] is consuming 95% of = CPU. This is=20 preventing the PHY autonegotiation (which is scheduled as a delayed wor= k) to start, so=20 the PHY is never ready and the packet never reaches the network. I was wondering if this situation resembles what the patch by Ingo Moln= ar "tasklet/rt:=20 Prevent tasklets from going into infinite spin in RT" describes. This patch is already in 2.6.31.12-rt21 patch which I'm using so either= it is a=20 different problem or a corner case of the same issue. Could anyone tell whether it is the same or a different problem? Thank you --=20 H=E9ctor Palacios -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html