From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752130AbdKHLf0 (ORCPT ); Wed, 8 Nov 2017 06:35:26 -0500 Received: from mx1.redhat.com ([209.132.183.28]:59160 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751826AbdKHLfY (ORCPT ); Wed, 8 Nov 2017 06:35:24 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7D136356C1 Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=sgruszka@redhat.com Date: Wed, 8 Nov 2017 12:35:22 +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: <20171108113521.GD2641@redhat.com> References: <1509983829.10974.2.camel@gmail.com> <20171107085327.GA11380@redhat.com> <20171107101320.GA12140@redhat.com> <1510052483.24015.1.camel@gmail.com> <20171108103729.GA2641@redhat.com> <1510139235.10467.1.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: <1510139235.10467.1.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 [10.5.110.30]); Wed, 08 Nov 2017 11:35:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 08, 2017 at 12:07:15PM +0100, Richard Genoud wrote: > > 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 > > Well, there's clearly a misunderstanding here : > After the command "echo 1-2.2 > /sys/bus/usb/drivers/usb/unbind" > I can't type *anything* > The only thing I can do is plug off the board. > This command never returns, so I can't stop the tracing... > > Or I missed something ? > > (maybe if there was more than one CPU on the board, I could do > something, but that's not the case) I was not aware that soft-lock up can hung the system. Below patch should prevent/help with the issue. This is not right fix, it's for futher debugging. Regards Stanislaw diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c index e2f4f5778267..d76ca608c722 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00usb.c @@ -321,8 +321,8 @@ static bool rt2x00usb_kick_tx_entry(struct queue_entry *entry, void *data) status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC); if (status) { - if (status == -ENODEV) - clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags); + printk("submit TX urb ERROR %d\n", status); + clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags); set_bit(ENTRY_DATA_IO_FAILED, &entry->flags); rt2x00lib_dmadone(entry); } @@ -410,8 +410,8 @@ static bool rt2x00usb_kick_rx_entry(struct queue_entry *entry, void *data) status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC); if (status) { - if (status == -ENODEV) - clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags); + printk("submit RX urb ERROR %d\n", status); + clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags); set_bit(ENTRY_DATA_IO_FAILED, &entry->flags); rt2x00lib_dmadone(entry); }