This makes bpf_dynptr_from_skb usable for tp_btf, so that we can easily parse skb in tracepoints. This has been discussed in [0], and Martin suggested to use dynptr (instead of helpers like bpf_skb_load_bytes). For safety, skb dynptr shouldn't be used in fentry/fexit. This is achieved by add KF_TRUSTED_ARGS flag in bpf_dynptr_from_skb defination, because pointers passed by tracepoint are trusted (PTR_TRUSTED) while those of fentry/fexit are not. Another problem raises that NULL pointers could be passed to tracepoint, such as trace_tcp_send_reset, and we need to recognize them. This is done by add a "__nullable" suffix in the func_proto of the tracepoint, discussed in [1]. 2 Test cases are added, one for "__nullable" suffix, and the other for using skb dynptr in tp_btf. changelog v1 -> v2: - Add "__nullable" suffix support (Alexei Starovoitov) - Replace "struct __sk_buff*" with "void*" in test (Martin KaFai Lau) [0] https://lore.kernel.org/all/20240205121038.41344-1-lulie@xxxxxxxxxxxxxxxxx/T/ [1] https://lore.kernel.org/all/20240430121805.104618-1-lulie@xxxxxxxxxxxxxxxxx/T/ Philo Lu (5): bpf: Support __nullable argument suffix for tp_btf selftests/bpf: Add test for __nullable suffix in tp_btf tcp: Use skb__nullable in trace_tcp_send_reset bpf: Allow bpf_dynptr_from_skb() for tp_btf selftests/bpf: Expand skb dynptr selftests for tp_btf include/trace/events/tcp.h | 12 +++---- kernel/bpf/btf.c | 13 +++++++ kernel/bpf/verifier.c | 36 +++++++++++++++++-- net/core/filter.c | 3 +- .../bpf/bpf_testmod/bpf_testmod-events.h | 6 ++++ .../selftests/bpf/bpf_testmod/bpf_testmod.c | 2 ++ .../testing/selftests/bpf/prog_tests/dynptr.c | 36 +++++++++++++++++-- .../selftests/bpf/prog_tests/module_attach.c | 14 +++++++- .../testing/selftests/bpf/progs/dynptr_fail.c | 25 +++++++++++++ .../selftests/bpf/progs/dynptr_success.c | 23 ++++++++++++ .../bpf/progs/test_module_attach_fail.c | 16 +++++++++ 11 files changed, 173 insertions(+), 13 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_module_attach_fail.c -- 2.32.0.3.g01195cf9f
