Re: [PATCH v5 0/6] enable creating [k,u]probe with perf_event_open

From: Daniel Borkmann
Date: Fri Dec 08 2017 - 14:58:09 EST


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
> instead.
>
> 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
> suggested.
>
> 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:
>
> https://www.linuxplumbersconf.org/2017/ocw/proposals/4808
>
> 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:
>
> https://github.com/liu-song-6/bcc/tree/perf_event_open

Peter / Stephen, I presume this will be routed through one of you, if
not please yell.

Thanks,
Daniel

> man-pages patch:
> perf_event_open.2: add type kprobe and uprobe
>
> bcc patch:
> bcc: Try use new API to create [k,u]probe with perf_event_open
>
> kernel patches:
>
> Song Liu (6):
> perf: prepare perf_event.h for new types perf_kprobe and perf_uprobe
> perf: copy new perf_event.h to tools/include/uapi
> perf: implement pmu perf_kprobe
> perf: implement pmu perf_uprobe
> bpf: add option for bpf_load.c to use perf_kprobe
> bpf: add new test test_many_kprobe
>
> include/linux/trace_events.h | 8 ++
> include/uapi/linux/perf_event.h | 4 +
> kernel/events/core.c | 131 +++++++++++++++++++++++-
> kernel/trace/trace_event_perf.c | 102 +++++++++++++++++++
> kernel/trace/trace_kprobe.c | 91 +++++++++++++++--
> kernel/trace/trace_probe.h | 11 ++
> kernel/trace/trace_uprobe.c | 86 ++++++++++++++--
> samples/bpf/Makefile | 3 +
> samples/bpf/bpf_load.c | 66 ++++++++++--
> samples/bpf/bpf_load.h | 14 +++
> samples/bpf/test_many_kprobe_user.c | 186 ++++++++++++++++++++++++++++++++++
> tools/include/uapi/linux/perf_event.h | 4 +
> 12 files changed, 677 insertions(+), 29 deletions(-)
> create mode 100644 samples/bpf/test_many_kprobe_user.c
>
> --
> 2.9.5
>