[for-next][PATCH 10/18] tracing: Uninitialized variable in create_tracing_map_fields()

From: Steven Rostedt
Date: Fri Apr 06 2018 - 09:04:57 EST

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

Smatch complains that idx can be used uninitialized when we check if
(idx < 0). It has to be the first iteration through the loop and the
HIST_FIELD_FL_STACKTRACE bit has to be clear and the HIST_FIELD_FL_VAR
bit has to be set to reach the bug.

Link: http://lkml.kernel.org/r/20180328114815.GC29050@mwanda

Fixes: 30350d65ac56 ("tracing: Add variable support to hist triggers")
Acked-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
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 15ea11c29a51..0d7b3ffbecc2 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -4458,7 +4458,7 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data)
struct tracing_map *map = hist_data->map;
struct ftrace_event_field *field;
struct hist_field *hist_field;
- int i, idx;
+ int i, idx = 0;

for_each_hist_field(i, hist_data) {
hist_field = hist_data->fields[i];