illumos gate

Quite a few dtrace SDT probes are missing argument types in their probe definitions. For example, all zfs SDT probes (though it's far from the only module):

[root@bob ~]# dtrace -vl -n sdt:zfs:dbuf_evict_one:dbuf-evict-one
   ID   PROVIDER            MODULE                          FUNCTION NAME
 7917        sdt               zfs                    dbuf_evict_one dbuf-evict-one

        Probe Description Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: ISA

        Argument Types
                None

For comparison,

[root@bob ~]# dtrace -vl -n op-Search-start
   ID   PROVIDER            MODULE                          FUNCTION NAME
 8955        smb            smbsrv                    smb_pre_search op-Search-start

        Probe Description Attributes
                Identifier Names: Private
                Data Semantics:   Private
                Dependency Class: Unknown

        Argument Attributes
                Identifier Names: Evolving
                Data Semantics:   Evolving
                Dependency Class: ISA

        Argument Types
                args[0]: conninfo_t *
                args[1]: smbopinfo_t *

This makes a significant number of SDT probes more difficult to use than they should be. Without the argument info, Dtrace cannot validate the correct use of the arguments to a probe and an operator must find the probe definitions in the source and manually cast the argN values.

It appears the problem is that arguments for all SDT probes in all modules must currently be defined in usr/src/uts/dtrace/sdt_subr.c.