On Tue, Nov 07, 2017 at 12:13:47PM +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. > Here is another trace, with rt2* as function filter. > (sorry for the noise) > > Dumping ftrace buffer: > --------------------------------- > CPU:0 [LOST 3606923 EVENTS] > 0) 0.000 us | } /* rt2x00usb_clear_entry */ > 0) 0.000 us | } /* rt2x00lib_rxdone */ > 0) 0.000 us | rt2x00queue_get_entry(); > 0) | rt2x00lib_rxdone() { > 0) 0.000 us | rt2x00queue_index_inc(); > 0) | rt2x00usb_clear_entry() { > 0) | rt2x00usb_kick_rx_entry() { We do that only if: if (test_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags) && test_bit(DEVICE_STATE_ENABLED_RADIO, &rt2x00dev->flags)) rt2x00dev->ops->lib->clear_entry(entry); so looks like DEVICE_STATE_PRESENT is not cleared. That mean usb driver do not call disconnect callback on unbind. That seems to be usb driver bug. Anyway please provide requested traces, so I will see what happen. Stanislaw
