Samba 3.6.4 tdb question

[Herb Lewis]

The file lib/tdb/common/tdb.c has a comment before the function 
tdb_parse_record

* DON'T CALL OTHER TDB CALLS FROM THE PARSER, THIS MIGHT LEAD TO SEGFAULTS.

can someone explain exactly what this means? Exactly what calls are not 
allowed?
I've run into a case where I get a segfault because tdb_parse_record 
ends up calling
tdb_lock_list which then calls tdb_needs_recovery which tries to do a 
tdb_read which
then gets a segfault. So it looks like I've hit this condition.