tracing: Change synthetic event string format to limit printed length
Change the format for printing synthetic field strings to limit the
length of the string printed even if it's not correctly terminated.
Description from Steve:
I also added this for a bit of paranoid, and probably should be a
separate patch, just to make sure if the string isn't nul terminated,
this will keep it from bleeding pass the end of the string.
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 24bc6d6..742ce5f 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -234,7 +234,7 @@ static const char *synth_field_fmt(char *type)
else if (strcmp(type, "gfp_t") == 0)
fmt = "%x";
else if (synth_field_is_string(type))
- fmt = "%s";
+ fmt = "%.*s";
return fmt;
}
@@ -303,11 +303,13 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
str_field = (char *)entry + data_offset;
trace_seq_printf(s, print_fmt, se->fields[i]->name,
+ STR_VAR_LEN_MAX,
str_field,
i == se->n_fields - 1 ? "" : " ");
n_u64++;
} else {
trace_seq_printf(s, print_fmt, se->fields[i]->name,
+ STR_VAR_LEN_MAX,
(char *)&entry->fields[n_u64],
i == se->n_fields - 1 ? "" : " ");
n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
