Comment # 7 on bug 1232536 from Anthony Iliopoulos

(In reply to Anthony Iliopoulos from comment #6)
> Looks related to dynamic linking (in this case we link bash against
> readline).
> 
> I suppose bpftrace does not resolve symbols from dynamically linked
> libraries. 

to make the above more clear:

when e.g. bash is dynamically linked against readline, then the readline
symbol is undefined before dynamic linking takes place at runtime, and
bpftrace (via libbcc) doesn't seem to implement resolution of dynamic
symbols.

the script works fine as-is when bash links statically against readline.

the script also works for dynamically linked bash/readline if one changes the
probe format to point directly to the shared library (which is what I did  in
[1]).

[1] https://bugzilla.suse.com/show_bug.cgi?id=1224403#c6