tracing: Fix unsigned comparison to zero in hist trigger code

Fengguang Wu's bot found two comparisons of unsigned integers to zero. These
were real bugs, as it would miss error conditions returned to zero.

trace_events_hist.c:426:6-9: WARNING: Unsigned expression compared with zero: idx < 0
trace_events_hist.c:568:5-14: WARNING: Unsigned expression compared with zero: n_entries < 0

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 23df38aab50375f7d6914b2407d4b78b5793d1d1..f98b6b3a28042a76538d2a670fd22b9aacaf184d 100644 (file)
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -734,7 +734,7 @@ 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;
-       unsigned int i, idx;
+       int i, idx;
 
        for_each_hist_field(i, hist_data) {
                hist_field = hist_data->fields[i];
@@ -1036,7 +1036,7 @@ static int print_entries(struct seq_file *m,
 {
        struct tracing_map_sort_entry **sort_entries = NULL;
        struct tracing_map *map = hist_data->map;
-       unsigned int i, n_entries;
+       int i, n_entries;
 
        n_entries = tracing_map_sort_entries(map, hist_data->sort_keys,
                                             hist_data->n_sort_keys,