From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751841AbdKHKhi (ORCPT ); Wed, 8 Nov 2017 05:37:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48650 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751344AbdKHKhg (ORCPT ); Wed, 8 Nov 2017 05:37:36 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 411177E380 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=sgruszka@redhat.com Date: Wed, 8 Nov 2017 11:37:30 +0100 From: Stanislaw Gruszka To: Richard Genoud Cc: Helmut Schaa , "linux-kernel@vger.kernel.org" , linux-wireless@vger.kernel.org Subject: Re: Soft lockup in rt2x00usb_work_rxdone() Message-ID: <20171108103729.GA2641@redhat.com> References: <1509983829.10974.2.camel@gmail.com> <20171107085327.GA11380@redhat.com> <20171107101320.GA12140@redhat.com> <1510052483.24015.1.camel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1510052483.24015.1.camel@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 08 Nov 2017 10:37:36 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 07, 2017 at 12:01:23PM +0100, Richard Genoud wrote: > Le mardi 07 novembre 2017 à 11:13 +0100, Stanislaw Gruszka a écrit : > > On Tue, Nov 07, 2017 at 11:06:39AM +0100, Richard Genoud wrote: > > > > 3 short articles how to configure and use ftrace are here: > > > > https://lwn.net/Articles/365835/ > > > > https://lwn.net/Articles/366796/ > > > > https://lwn.net/Articles/370423/ > > > > > > > > > > I tried with ftrace, but I don't think there's a way to dump the > > > trace > > > when there's a soft lock-up > > > (I can't do anything after the unbind, even the heartbeat led > > > stopped blinking). > > > I saw the /proc/sys/kernel/ftrace_dump_on_oops file, but there's no > > > /proc/sys/kernel/ftrace_dump_on_soft_lock-up file :) > > > > You should configure function trace with rt2x* functions. After that > > start tracing, unbind the device, then stop tracing and provide trace > > output. > Ok, I found a way to display the trace (after the unbind, the board is > frozen and I can't type anything). > Adding > CONFIG_SOFTLOCKUP_DETECTOR=y > CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y > along with echo 1 > /proc/sys/kernel/ftrace_dump_on_oops does the trick No, that not I wanted you to do. Please remove those options and just do below on tracing directory. echo 0 > tracing_on cat trace > /dev/null echo "function_graph" > current_tracer echo "rt2*" > set_ftrace_filter echo 1 > tracing_on echo 1-2.2 > /sys/bus/usb/drivers/usb/unbind echo 0 > tracing_on cat trace > ~/trace.txt and provide trace.txt to me (can be in private email if big). Thanks Stanislaw