hi, Tracing programs can access arguments via BTF [1]. Currently we allow tracing programs to access pointers to string (char pointer), void pointers, pointers to structs, and int pointers [2]. If we try to access argument which is pointer to const void like 2nd argument in kfree, it's an UNKNOWN type, verifier will fail to load. typedef void (*btf_trace_kfree)(void *, long unsigned int, const void *); [1] https://lore.kernel.org/bpf/20191016032505.2089704-7-ast@xxxxxxxxxx/ [2] https://lore.kernel.org/bpf/20211208193245.172141-1-jolsa@xxxxxxxxxx/ --- KaFai Wan (2): bpf: Allow access to const void pointer arguments in tracing programs selftests/bpf: Add test to access const void pointer argument in tracing program kernel/bpf/btf.c | 10 +++++++++- .../selftests/bpf/progs/verifier_btf_ctx_access.c | 9 +++++++++ 2 files changed, 18 insertions(+), 1 deletion(-) -- 2.43.0
