dyndbg: fix old BUG_ON in >control parser

commit 00e7d3bea2ce7dac7bee1cf501fb071fd0ea8f6c upstream.

Fix a BUG_ON from 2009.  Even if it looks "unreachable" (I didn't
really look), lets make sure by removing it, doing pr_err and return
-EINVAL instead.

Cc: stable <[email protected]>
Signed-off-by: Jim Cromie <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 009f2ea..939678e 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -301,7 +301,11 @@ static int ddebug_tokenize(char *buf, char *words[], int maxwords)
 		} else {
 			for (end = buf; *end && !isspace(*end); end++)
 				;
-			BUG_ON(end == buf);
+			if (end == buf) {
+				pr_err("parse err after word:%d=%s\n", nwords,
+				       nwords ? words[nwords - 1] : "<none>");
+				return -EINVAL;
+			}
 		}
 
 		/* `buf' is start of word, `end' is one past its end */