It might be related to the static linking of lttng-ust
https://lists.lttng.org/pipermail/lttng-dev/2018-January/027705.html

I also went down that path just to figure it’s not supported.
Perhaps lttng documentation should be updated to make a clear note static 
linking is not supported (or maybe I missed it)

Yehuda

Hi,

I'm on an embedded platform, i.MX8 using Lttng 2.11 with 5.6.69 kernel.

Tracing kernel events with lttng works fine but userspace (tracef and trace 
provider type tracing) appears to have an issue I can't figure out.

systemd is starting up my application ( a bunch of processes and threads on 
multiple cpu's) on boot.

I'm statically compiling and linking in lttng-ust.  If I use just tracef type 
tracing, when I do lttng list --userspace I get nothing.  If I add in a trace 
provider and a tracepoint, then I see my trace provider tracepoint and:

     lttng_ust_tracelog:TRACE_DEBUG (loglevel: TRACE_DEBUG (14)) (type: 
tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_LINE (loglevel: TRACE_DEBUG_LINE (13)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_FUNCTION (loglevel: TRACE_DEBUG_FUNCTION 
(12)) (type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_UNIT (loglevel: TRACE_DEBUG_UNIT (11)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_MODULE (loglevel: TRACE_DEBUG_MODULE (10)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_PROCESS (loglevel: TRACE_DEBUG_PROCESS (9)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_PROGRAM (loglevel: TRACE_DEBUG_PROGRAM (8)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_DEBUG_SYSTEM (loglevel: TRACE_DEBUG_SYSTEM (7)) 
(type: tracepoint)
     lttng_ust_tracelog:TRACE_INFO (loglevel: TRACE_INFO (6)) (type: tracepoint)
     lttng_ust_tracelog:TRACE_NOTICE (loglevel: TRACE_NOTICE (5)) (type: 
tracepoint)
     lttng_ust_tracelog:TRACE_WARNING (loglevel: TRACE_WARNING (4)) (type: 
tracepoint)
     lttng_ust_tracelog:TRACE_ERR (loglevel: TRACE_ERR (3)) (type: tracepoint)
     lttng_ust_tracelog:TRACE_CRIT (loglevel: TRACE_CRIT (2)) (type: tracepoint)
     lttng_ust_tracelog:TRACE_ALERT (loglevel: TRACE_ALERT (1)) (type: 
tracepoint)
     lttng_ust_tracelog:TRACE_EMERG (loglevel: TRACE_EMERG (0)) (type: 
tracepoint)
     lttng_ust_tracef:event (loglevel: TRACE_DEBUG (14)) (type: tracepoint)
     lttng_ust_lib:unload (loglevel: TRACE_DEBUG_LINE (13)) (type: tracepoint)
     lttng_ust_lib:debug_link (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)
     lttng_ust_lib:build_id (loglevel: TRACE_DEBUG_LINE (13)) (type: tracepoint)
     lttng_ust_lib:load (loglevel: TRACE_DEBUG_LINE (13)) (type: tracepoint)
     lttng_ust_statedump:end (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)
     lttng_ust_statedump:debug_link (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)
     lttng_ust_statedump:build_id (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)
     lttng_ust_statedump:bin_info (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)
     lttng_ust_statedump:start (loglevel: TRACE_DEBUG_LINE (13)) (type: 
tracepoint)

When I do lttng start, I get a directory structure in the trace directory but 
the file sizes do not ever increase.  It's just a directory structure with 
files created and then that's it, no events being written to the files.  At 
first I thought things just weren't linked in right and not working but then 
discovered how to run lttng-sessiond in -vvv mode and then could see lots of 
things are going on, tracing appears to be trying to work as there is tons of 
activity being output by lttng-sessiond, but like I said the trace files aren't 
being added to.

I looked at the lttng-sessiond log I captured and can't quite make out the 
problem so attaching it.

I'm probably not doing something right but can't figure out what that is so any 
pointers appreciated.

Regards,

Brian

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