[for-next][PATCH 15/21] tracing: Return -EINVAL if WARN_ON(!glob) triggered in event_hist_trigger_parse()

[for-next][PATCH 15/21] tracing: Return -EINVAL if WARN_ON(!glob) triggered in event_hist_trigger_parse()

[Steven Rostedt]

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

If `WARN_ON(!glob)` is ever triggered, we will still continue executing
the next lines. This will trigger the more serious problem, a NULL
pointer dereference bug.

Just return -EINVAL if @glob is NULL.

Link: https://lkml.kernel.org/r/20220417185630.199062-2-ammarfaizi2@gnuweeb.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 998dfe2162fc..80c25be23c45 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6214,7 +6214,8 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
 
 	lockdep_assert_held(&event_mutex);
 
-	WARN_ON(!glob);
+	if (WARN_ON(!glob))
+		return -EINVAL;
 
 	if (strlen(glob)) {
 		hist_err_clear();
-- 
2.35.1

[for-next][PATCH 16/21] tracing: Change `if (strlen(glob))` to `if (glob[0])`

[Steven Rostedt]

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

No need to traverse to the end of string. If the first byte is not a NUL
char, it's guaranteed `if (strlen(glob))` is true.

Link: https://lkml.kernel.org/r/20220417185630.199062-3-ammarfaizi2@gnuweeb.org

Cc: Ingo Molnar <mingo@redhat.com>
Cc: GNU/Weeb Mailing List <gwml@vger.gnuweeb.org>
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 kernel/trace/trace_events_hist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 80c25be23c45..fe10179893c1 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -6217,7 +6217,7 @@ static int event_hist_trigger_parse(struct event_command *cmd_ops,
 	if (WARN_ON(!glob))
 		return -EINVAL;
 
-	if (strlen(glob)) {
+	if (glob[0]) {
 		hist_err_clear();
 		last_cmd_set(file, param_and_filter);
 	}
-- 
2.35.1