[dtrace] attaching to a PID

[Pan Tsu]

Does anyone else see the following crash?

  $ sh -c 'sleep 60& dtrace -P syscall -p $!'
  dtrace: description 'syscall' matched 2092 probes
  Assertion failed: (dpr != NULL), file
  .../cddl/contrib/opensolaris/lib/libdtrace/common/dt_proc.c, line 751.
  Exit 134

Also triggers without specifying PID, e.g. by ustack()

  $ dtrace -P 'syscall { @[probefunc,ustack()] = count(); }'

Not sure if I hosed my environment.

--
FreeBSD 9.0-CURRENT #0 r223522M amd64