[PATCH v2 bpf-next 0/3] veristat: add better support of freplace programs

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Teach veristat how to deal with freplace BPF programs. As they can't be
directly loaded by veristat without custom user-space part that sets correct
target program FD, veristat always fails freplace programs. This patch set
teaches veristat to guess target program type that will be inherited by
freplace program itself, and subtitute it for BPF_PROG_TYPE_EXT (freplace) one
for the purposes of BPF verification.

Patch #1 fixes bug in libbpf preventing overriding freplace with specific
program type.

Patch #2 adds convenient -d flag to request veristat to emit libbpf debug
logs. It help debugging why a specific BPF program fails to load, if the
problem is not due to BPF verification itself.

v1->v2:
  - fix compilation error reported by old GCC (my GCC v11 doesn't produce even
    a warning) and Clang (see CI failure at [0]):

GCC version:

  veristat.c: In function ‘fixup_obj’:
  veristat.c:908:1: error: label at end of compound statement
    908 | skip_freplace_fixup:
        | ^~~~~~~~~~~~~~~~~~~

Clang version:

  veristat.c:909:1: error: label at end of compound statement is a C2x extension [-Werror,-Wc2x-extensions]
  }
  ^
  1 error generated.

  [0] https://github.com/kernel-patches/bpf/actions/runs/4515972059/jobs/7953845335

Andrii Nakryiko (3):
  libbpf: disassociate section handler on explicit
    bpf_program__set_type() call
  veristat: add -d debug mode option to see debug libbpf log
  veristat: guess and substitue underlying program type for freplace
    (EXT) progs

 tools/lib/bpf/libbpf.c                 |   1 +
 tools/testing/selftests/bpf/veristat.c | 126 ++++++++++++++++++++++++-
 2 files changed, 122 insertions(+), 5 deletions(-)

-- 
2.34.1




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