Re: Ftrace and Systemtap

[fche at redhat dot com (Frank Ch. Eigler)]

Masami Hiramatsu <mhiramat@redhat.com> writes:

>> I always hear complaints which systemtap can't be used for the latest
>> developing kernel. And yes, that's true.
>
> It will happen on a personal development branch. (note that
> all developments are started on a personal branch :))
> Not(or rarely) on public linus/linux-next tree.
>
> If someone changes some APIs which  systemtap depends on,
> systemtap can't work on his kernel.
> e.g. just removing EXPORT_SYMBOL_GPL(register_kprobe).
>
> This also shows why the out-of-tree driver is so fragile.

In theory, that makes a lot of sense.

But you made it sound like in practice it is problematic ("That is
true.").  Please provide some substantiation of this, for anecdotes
are all I've heard lately.  What versions have not worked / when / for
how long?  Who has removed EXPORT_SYMBOL* something essential to
systemtap (which by the way kprobes aren't)?


- FChE