tracing/filters: Fix MATCH_MIDDLE_ONLY filter matching

The @str might not be NULL-terminated if it's of type
DYN_STRING or STATIC_STRING, so we should use strnstr()
instead of strstr().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4B4E8753.2000102@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 49e44dd17851..f364b085397e 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -268,7 +268,7 @@ static int regex_match_front(char *str, struct regex *r, int len)
 
 static int regex_match_middle(char *str, struct regex *r, int len)
 {
-        if (strstr(str, r->pattern))
+        if (strnstr(str, r->pattern, len))
                 return 1;
         return 0;
 }