[PATCH bpf-next v1 0/3] Avoid typedef size mismatches in skeletons

[Delyan Kratunov <delyank@fb.com>]

As reported in [0], kernel and userspace can sometimes disagree
on the definition of a typedef (in particular, the size).
This leads to trouble when userspace maps the memory of a bpf program
and reads/writes to it assuming a different memory layout.

This series resolves most int-like typedefs and rewrites them as
standard int16_t-like types. In particular, we don't touch
__u32-like types, char, and _Bool, as changing them changes cast
semantics and would break too many pre-existing programs. For example,
int8_t* is not convertible to char* because int8_t is explicitly signed.

  [0]: https://github.com/iovisor/bcc/pull/3777

Delyan Kratunov (3):
  libbpf: btf_dump can produce explicitly sized ints
  bpftool: skeleton uses explicitly sized ints
  selftests/bpf: add test case for userspace and bpf type size mismatch

 tools/bpf/bpftool/gen.c                       |  3 +
 tools/lib/bpf/btf.h                           |  4 +-
 tools/lib/bpf/btf_dump.c                      | 80 ++++++++++++++++++-
 .../selftests/bpf/prog_tests/skeleton.c       | 22 +++--
 .../selftests/bpf/progs/test_skeleton.c       |  8 ++
 5 files changed, 107 insertions(+), 10 deletions(-)

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2.34.1