dtrace showed matched probes but nothing in output on FreeBSD 9.1-RELEASE

[Mark Johnston]

On Tue, Nov 05, 2013 at 02:47:58PM +0800, John Luk wrote:
> Hi, Mark. The gdb output is included below. I'm wondering why dtrace -l can
> trace all my function correctly but the D script failed. Is it because they get
> the symbol table in different way?

Hm, I can't reproduce the problem using your binary on a machine running
head. I suspect the problem has to do with some other DTrace bugs in the
kernel which have been recently fixed - there were a couple that would
corrupt the state of traced programs in various ways, and it could be
that inet_makeaddr() really isn't getting called as a result. You could
try adding a printf or something to see if that's the case.

In general there have been quite a few DTrace fixes since 9.1, so it's
worth trying out newer revisions if you're interested in trying out
DTrace on FreeBSD.

-Mark