1. UTRACE_ATTACH_MATCH_DATA is not used.
2. s/utrace_attached_engine/utrace_engine/g
Engine which is not attached is either just allocated or scheduled
for freeing
3. get_utrace_lock() is funny.
From name one should get valid struct utrace or -E depending only on
task, why engine matters is a mystery.
4. subsys_initcall
Just use module_init() or comment why it's needed.
5. Dummy in examiner -- not used (of course!)
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