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
