# Re: \[PATCH v11 tip 6/9\] samples: bpf: simple non-portable kprobe filter example

- From: Alexei Starovoitov \<hidden\>
- Date: 2015-03-30 01:00:01 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2015/03/4461683
- Thread: https://ratatoskr.run/linux-api/2015/03/4459384/t.md

```text
On 3/29/15 5:34 PM, Jovi Zhangwei wrote:
>> +               snprintf(buf, sizeof(buf),
>> +                        "echo '%c:%s %s' >> /sys/kernel/debug/tracing/kprobe_events",
>> +                        is_kprobe ? 'p' : 'r', event, event);
>> +               err = system(buf);
>
> Maybe we need to remember cleanup the kprobe_events in debugfs?

the real tracing tool should be cleaning it up. This is sample code.
I didn't want to overcomplicate it with a chain of ctrl-c handlers.
Notice patch 7 is simply doing signal(SIGINT, int_exit) and prints
histogram when process is terminated. The kprobe cleaning logic would
have interfere with this and overall would have made these samples
unnecessary complex.
```