Re: [PATCH v5 0/6] enable creating [k,u]probe with perf_event_open
From: Song Liu
Date: Tue Dec 19 2017 - 12:25:48 EST
> On Dec 8, 2017, at 11:57 AM, Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
> On 12/06/2017 11:45 PM, Song Liu wrote:
>> Changes PATCH v4 to PATCH v5:
>> Remove PERF_PROBE_CONFIG_IS_RETPROBE from uapi, use PMU_FORMAT_ATTR
>> Changes PATCH v3 to PATCH v4:
>> Remove uapi define MAX_PROBE_FUNC_NAME_LEN, use KSYM_NAME_LEN instead.
>> Add flag PERF_PROBE_CONFIG_IS_RETPROBE for config field of [k,u]probe.
>> Optimize ifdef's of CONFIG_KPROBE_EVENTS and CONFIG_UPROBE_EVENTS.
>> Optimize checks in perf_event_is_tracing().
>> Optimize perf_tp_register().
>> Changes PATCH v2 to PATCH v3:
>> Remove fixed type PERF_TYPE_KPROBE and PERF_TYPE_UPROBE, use dynamic
>> type instead.
>> Update userspace (samples/bpf, bcc) to look up type from sysfs.
>> Change License info in test_many_kprobe_user.c as Philippe Ombredanne
>> Changes PATCH v1 to PATCH v2:
>> Split PERF_TYPE_PROBE into PERF_TYPE_KPROBE and PERF_TYPE_UPROBE.
>> Split perf_probe into perf_kprobe and perf_uprobe.
>> Remove struct probe_desc, use config1 and config2 instead.
>> Changes RFC v2 to PATCH v1:
>> Check type PERF_TYPE_PROBE in perf_event_set_filter().
>> Rebase on to tip perf/core.
>> Changes RFC v1 to RFC v2:
>> Fix build issue reported by kbuild test bot by adding ifdef of
>> CONFIG_KPROBE_EVENTS, and CONFIG_UPROBE_EVENTS.
>> RFC v1 cover letter:
>> This is to follow up the discussion over "new kprobe api" at Linux
>> Plumbers 2017:
>> With current kernel, user space tools can only create/destroy [k,u]probes
>> with a text-based API (kprobe_events and uprobe_events in tracefs). This
>> approach relies on user space to clean up the [k,u]probe after using them.
>> However, this is not easy for user space to clean up properly.
>> To solve this problem, we introduce a file descriptor based API.
>> Specifically, we extended perf_event_open to create [k,u]probe, and attach
>> this [k,u]probe to the file descriptor created by perf_event_open. These
>> [k,u]probe are associated with this file descriptor, so they are not
>> available in tracefs.
>> We reuse large portion of existing trace_kprobe and trace_uprobe code.
>> Currently, the file descriptor API does not support arguments as the
>> text-based API does. This should not be a problem, as user of the file
>> decriptor based API read data through other methods (bpf, etc.).
>> I also include a patch to to bcc, and a patch to man-page perf_even_open.
>> Please see the list below. A fork of bcc with this patch is also available
>> on github:
> Peter / Stephen, I presume this will be routed through one of you, if
> not please yell.
Do you have further feedbacks/comments on these patches? If not, could you
please confirm they are ready for merge?
Thanks and Best Regards,