When a dyndbg classname is unknown to a kernel module, the callsite is
un-addressable via >control queries, and therefore uncontrollable.

The control-file displays this condition as "class unknown, _id:N"
currently.  That spelling is sub-optimal/too-generic, so change it to
"class:_UNKNOWN_ _id:N" to loudly announce the erroneous situation,
and to make it uniquely greppable.

NB: while this might be seen as a user-visible change, this shouldn't
disqualify the change:

a- it reports a classmap coding error condition, which should be
   detected in (or before) review.
b- SHOUTING the error makes it more visible, uniquely greppable.
c- the classmap feature is marked BROKEN for its only current user.

Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com>
---
 lib/dynamic_debug.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 577a07916072..a86e1d5845e6 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c

@@ -1170,7 +1170,7 @@ static int ddebug_proc_show(struct seq_file *m, void *p)
 		if (class)
 			seq_printf(m, " class:%s", class);
 		else
-			seq_printf(m, " class unknown, _id:%d", dp->class_id);
+			seq_printf(m, " class:_UNKNOWN_ _id:%d", dp->class_id);
 	}
 	seq_putc(m, '\n');
 

-- 
2.55.0