Le mercredi 08 novembre 2017 à 11:37 +0100, Stanislaw Gruszka a écrit : > 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 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) > > and provide trace.txt to me (can be in private email if big). > > Thanks > Stanislaw Thanks, Richard.
