[PATCH bpf-next v3 00/11] Unify subprog argument checks

[Amery Hung <ameryhung@gmail.com>]

Hi,

Helper and kfunc calls now validate arguments through check_func_args(),
while subprog calls still duplicate much of the same validation in
btf_check_func_arg_match(). This makes common argument rules and
diagnostics easy to change for one call kind without updating the other.

This series builds a temporary helper-style argument prototype from the
subprog's cached BTF metadata, then moves each supported argument class to
the common checker. The last patch removes the duplicate loop.

The series is organized as follows:

- Patch 1 fixes kfunc BTF parameter lookups after wide arguments.
- Patches 2-3 identify subprog calls in common metadata and generate the
  temporary argument prototype.
- Patches 4-9 move scalar, untrusted, context, arena, dynptr, and BTF-ID
  arguments to the common path.
- Patch 10 moves global subprog memory arguments and their packet-change
  check to the common path.
- Patch 11 removes the legacy loop and checks all subprog arguments through
  check_func_args().

This follows the helper/kfunc argument-checking consolidation:
https://lore.kernel.org/bpf/20260911220415.1396439-1-ameryhung@gmail.com/

v2 -> v3:
  - Remove the redundant dynptr register-type check from
    process_dynptr_func() after all callers begin using check_func_arg()
    (Sashiko)
  Link: https://lore.kernel.org/bpf/20260928181414.644158-1-ameryhung@gmail.com/

v1 -> v2:
  - Extend patch 1 to fix the release and iterator BTF parameter lookups
    after wide arguments (Alexei)
  - Keep subprog call metadata local to argument checking, leaving callers
    and helper/kfunc handling unchanged (Alexei)
  Link: https://lore.kernel.org/bpf/20260925211256.1834061-1-ameryhung@gmail.com/

Amery Hung (11):
  bpf: Fix kfunc BTF parameter lookups after wide arguments
  bpf: Identify subprog calls in argument metadata
  bpf: Build argument prototypes for subprog calls
  bpf: Check subprog scalar arguments in the common path
  bpf: Check global subprog untrusted arguments in the common path
  bpf: Check subprog context arguments in the common path
  bpf: Check subprog arena arguments in the common path
  bpf: Check subprog dynptr arguments in the common path
  bpf: Check global subprog BTF-ID arguments in the common path
  bpf: Check global subprog memory arguments in the common path
  bpf: Check all subprog arguments in the common path

 include/linux/bpf_verifier.h                  |   6 +-
 kernel/bpf/verifier.c                         | 283 +++++++-----------
 .../selftests/bpf/progs/aggregate_arg_func.c  |   2 +-
 .../testing/selftests/bpf/progs/dynptr_fail.c |  11 +-
 .../selftests/bpf/progs/test_global_func5.c   |   2 +-
 .../bpf/progs/verifier_global_ptr_args.c      |   7 +-
 .../bpf/progs/verifier_global_subprogs.c      |   2 +-
 7 files changed, 129 insertions(+), 184 deletions(-)

-- 
2.52.0