[PATCH bpf-next 0/4] Fix perf_buffer creation on systems with offline CPUs

[Andrii Nakryiko <andriin@fb.com>]

This patch set fixes perf_buffer__new() behavior on systems which have some of
the CPUs offline/missing (due to difference between "possible" and "online"
sets). perf_buffer will create per-CPU buffer and open/attach to corresponding
perf_event only on CPUs present and online at the moment of perf_buffer
creation. Without this logic, perf_buffer creation has no chances of
succeeding on such systems, preventing valid and correct BPF applications from
starting.

Andrii Nakryiko (4):
  libbpf: extract and generalize CPU mask parsing logic
  selftests/bpf: add CPU mask parsing tests
  libbpf: don't attach perf_buffer to offline/missing CPUs
  selftests/bpf: fix perf_buffer test on systems w/ offline CPUs

 tools/lib/bpf/libbpf.c                        | 157 ++++++++++++------
 tools/lib/bpf/libbpf_internal.h               |   2 +
 .../selftests/bpf/prog_tests/cpu_mask.c       |  78 +++++++++
 .../selftests/bpf/prog_tests/perf_buffer.c    |  29 +++-
 4 files changed, 213 insertions(+), 53 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/cpu_mask.c

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2.17.1