Hi Steven,

When tracing I get these error messages and no trace data is recorded. I 
also cloned the trace-cmd repo and tried that with the same result. I 
think the kernel configuration looks ok, but adding it.

I use it almost daily on Ubuntu system, but trying Fedora for a change. 
I do have a difference with kernel taint with my driver loaded:

Ubuntu	4096	(OOT module loaded, ie. my driver)
Fedora	4098	(OOT *and* forced module?)

'forced module' probably caused by:
[10808.074823] Request for unknown module key 'Fedora kernel signing 
key: 8661dbf3061bfa70eb76d61691cec200318534b4' err -11

Would that explain my issue?

Regards,
Arend

---8<----------------------------------------------------
$ sudo trace-cmd record -e brcmfmac:*
/sys/kernel/debug/tracing/events/brcmfmac/*/filter
Hit Ctrl^C to stop recording
^Ctrace-cmd: Interrupted system call
trace-cmd: Interrupted system call
     recorder error in splice inputrecorder error in splice input

trace-cmd: Interrupted system call
   recorder error in splice input
trace-cmd: Interrupted system call
   recorder error in splice input
Kernel buffer statistics:
   Note: "entries" are the entries left in the kernel ring buffer and 
are not
         recorded in the trace data. They should all be zero.