Can't attach to multiple kernel functions with the same name

[ajor]

Choose a function which has duplicates in kallsyms:

$ grep '\<s_next\>' /proc/kallsyms
ffffffff812a6b40 t s_next
ffffffff81469630 t s_next
ffffffff815bdf60 t s_next
ffffffff81759010 t s_next
ffffffff817eeed0 t s_next

Trace and print the address of the function we've attached to:

# bpftrace -e 'kprobe:s_next { printf("%x\n", reg("ip")) }'
Attaching 1 probe...
812a6b41
812a6b41
812a6b41
812a6b41
[...]

(this probe can be triggered by running $ grep '\<s_next\>' /proc/kallsyms again)

We only appear to trace the first entry in kallsyms.

Should we attach to all instances or error out instead?

Related to #3140