The %K and %U format specifiers can be used in a trace
format string to resolve kernel and user symbols,
respectively. For example, the pthread_create USDT probe
has an argument pointing to the new thread's function.
To trace pthread_create and print the symbolic name of
the new thread's function, use:

```
trace 'u:pthread:pthread_create "%U", arg3'
```

The %U specifier resolves addresses in the event's process,
while the %K specifier resolves kernel addresses.