On Fri, Nov 19, 2021 at 03:44:34PM +0100, Steven Rostedt wrote:
> On Fri, 19 Nov 2021 12:24:20 +0100
> Vincent Whitchurch <vincent.whitchurch@xxxxxxxx> wrote:
>
> > Do not segfault if the event cannot be found for some reason and
> > tep_find_event_by_record() returns NULL.
> >
> > No extra warning is added since there are others ("UNKNOWN EVENT") which
> > already make it clear that something is wrong:
> >
> > kworker/u8:0-7 [003] 1.245773: sched_stat_runtime: comm=kworker/u8:...
> > [UNKNOWN EVENT][UNKNOWN EVENT][UNKNOWN EVENT]
> > kworker/u8:0-7 [003] 1.245776: sched_switch: kworker/u8:0:7 [120] W...
> >
>
> I wonder if the following would be a better and more robust approach:
>
> diff --git a/tracecmd/trace-read.c b/tracecmd/trace-read.c
> index f7ffb89e..4b27740a 100644
> --- a/tracecmd/trace-read.c
> +++ b/tracecmd/trace-read.c
> @@ -142,12 +142,15 @@ static struct trace_hash wakeup_hash;
> static void print_event_name(struct trace_seq *s, struct tep_event *event)
> {
> static const char *spaces = " "; /* 20 spaces */
> + const char *name;
> int len;
>
> - trace_seq_printf(s, " %s: ", event->name);
> + name = event ? event->name : "(NULL)";
> +
> + trace_seq_printf(s, " %s: ", name);
>
> /* Space out the event names evenly. */
> - len = strlen(event->name);
> + len = strlen(name);
> if (len < 20)
> trace_seq_printf(s, "%.*s", 20 - len, spaces);
> }
Looks good to me.
|