LTTng » LTTng-tools

I encountered a deadlock of the session daemon when tracing short lived UST app in burst. I was not able to reproduce it.
Here is the session configuration:

lttng create allo --live
lttng enable-channel --buffers-pid -s allo --tracefile-size=5M --tracefile-count=4 -u chan1
lttng enable-event -u -a -c chan1
lttng start allo

After configured this session, I ran the following for loop followed by a lttng destroy command. As such:

for i in `seq 1 10`; do
   ../../../lttng-emojis/main & ;
done;
lttng destroy -a

These apps run and exit very quickly. The lttng destroy command never completes .

I attached the source code of the app as well as the backtraces of both lttng session daemon and the lttng consumer daemon.

We gathered so far:
sessiond thread 8: waiting on consumer socket (recv), while holding the consumer socket lock
sessiond thread 11: waiting for socket lock, while holding ust registry lock
sessiond thread 15: waiting for ust registry lock

consumerd thread 4: waiting for stream lock
consumerd thread 7: waiting on consumer metadata socket(recv), while holding stream lock
consumerd thread 8: waiting for stream lock

I was running this lttng-tools branch: https://github.com/PSRCode/lttng-tools/tree/live-per-pid (commit f0e3b9ebe)