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Subject: [PATCH v2 bpf-next 0/2] bpf: fix stackmap on perf_events with PEBS
Date:   Tue, 14 Jul 2020 22:25:59 -0700
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Calling get_perf_callchain() on perf_events from PEBS entries may cause
unwinder errors. To fix this issue, perf subsystem fetches callchain earl=
y,
and marks perf_events are marked with __PERF_SAMPLE_CALLCHAIN_EARLY.
Similar issue exists when BPF program calls get_perf_callchain() via
helper functions. For more information about this issue, please refer to
discussions in [1].

This set fixes this issue with helper proto bpf_get_stackid_pe and
bpf_get_stack_pe.

[1] https://lore.kernel.org/lkml/ED7B9430-6489-4260-B3C5-9CFA2E3AA87A@fb.=
com/

Changes v1 =3D> v2:
1. Simplify the design and avoid introducing new helper function. (Andrii=
)

Song Liu (2):
  bpf: separate bpf_get_[stack|stackid] for perf events BPF
  selftests/bpf: add callchain_stackid

 include/linux/bpf.h                           |   2 +
 kernel/bpf/stackmap.c                         | 204 ++++++++++++++++--
 kernel/trace/bpf_trace.c                      |   4 +-
 .../bpf/prog_tests/perf_event_stackmap.c      | 120 +++++++++++
 .../selftests/bpf/progs/perf_event_stackmap.c |  64 ++++++
 5 files changed, 374 insertions(+), 20 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_event_sta=
ckmap.c
 create mode 100644 tools/testing/selftests/bpf/progs/perf_event_stackmap=
.c

--
2.24.1