On Thu, Jun 15, 2023 at 6:04 PM Jiri Olsa [off-list ref] wrote:

On Mon, Jun 12, 2023 at 03:15:58PM +0000, Yafang Shao wrote:

quoted

This patchset enhances the usability of kprobe_multi programs by introducing
support for ->fill_link_info. This allows users to easily determine the
probed functions associated with a kprobe_multi program. While
`bpftool perf show` already provides information about functions probed by
perf_event programs, supporting ->fill_link_info ensures consistent access to
this information across all bpf links.

In addition, this patch extends support to generic perf events, which are
currently not covered by `bpftool perf show`. While userspace is exposed to
only the perf type and config, other attributes such as sample_period and
sample_freq are disregarded.

To ensure accurate identification of probed functions, it is preferable to
expose the address directly rather than relying solely on the symbol name.
However, this implementation respects the kptr_restrict setting and avoids
exposing the address if it is not permitted.

v2->v3:
- Expose flags instead of retporbe (Andrii)
- Simplify the check on kmulti_link->cnt (Andrii)
- Use kallsyms_show_value() instead (Andrii)
- Show also the module name for kprobe_multi (Andrii)
- Add new enum bpf_perf_link_type (Andrii)
- Move perf event names into bpftool (Andrii, Quentin, Jiri)
- Keep perf event names in sync with perf tools (Jiri)

hi,
I'm getting some failing tests with this version:

#11/2    bpf_cookie/multi_kprobe_link_api:FAIL
#11/3    bpf_cookie/multi_kprobe_attach_api:FAIL
#11      bpf_cookie:FAIL

#104/1   kprobe_multi_test/skel_api:FAIL
#104/2   kprobe_multi_test/link_api_addrs:FAIL
#104/3   kprobe_multi_test/link_api_syms:FAIL
#104/4   kprobe_multi_test/attach_api_pattern:FAIL
#104/5   kprobe_multi_test/attach_api_addrs:FAIL
#104/6   kprobe_multi_test/attach_api_syms:FAIL
#104     kprobe_multi_test:FAIL
#105/1   kprobe_multi_testmod_test/testmod_attach_api_syms:FAIL
#105/2   kprobe_multi_testmod_test/testmod_attach_api_addrs:FAIL
#105     kprobe_multi_testmod_test:FAIL

Thanks for your report.
BPF CI catched these errors as well.
That is caused by setting link->fp.flags, which has been pointed out
by you in patch #1.
I will fix it in the next version.

--
Regards

Yafang