[PATCH 1/2] dyndbg: dont panic over bad input

[Jim Cromie]

This BUG_ON, from 2009, caught the impossible case of a word-char both
starting and ending a string (loosely speaking).  A bad (reverted)
patch finally hit this case, but even "impossibly bad input" is no
reason to panic the kernel.  Instead pr_err and return -EINVAL.

Reported-by: Petr Mladek <pmla...@suse.com>
Signed-off-by: Jim Cromie <jim.cro...@gmail.com>
---
 lib/dynamic_debug.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 2d4dfd44b0fa5..90ddf07ce34fe 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -259,7 +259,10 @@ 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("expected non-empty bareword");
+                               return -EINVAL;
+                       }
                }
 
                /* `buf' is start of word, `end' is one past its end */
-- 
2.26.2