Re: Soft lockup in rt2x00usb_work_rxdone()

[Stanislaw Gruszka]

Hi

On Mon, Nov 06, 2017 at 04:57:09PM +0100, Richard Genoud wrote:
> I get a soft lock-up while unbinding the USB driver on a TP-Link TL-WN727Nv3 (chipset 5370):
> 
> # echo 1-2.2 > /sys/bus/usb/drivers/usb/unbind
> watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/u2:3:308]
...
> I can trigger this each time.

I can not reproduce this on my system (I'm using 4.14.0-rc6, but I don't
think it's an issue). I think the problem may be caused by usb
host controler driver, which can be different on your system.

Does ftrace work on your platform ? If so could you use ftrace
to provide rt2x00 functions trace when the  probllem happen ? 

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/

Thanks
Stanislaw