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[bpf-next,0/2] bpf: Allow skb dynptr for tp_btf

Message ID 20240430121805.104618-1-lulie@linux.alibaba.com (mailing list archive)
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Series bpf: Allow skb dynptr for tp_btf | expand

Message

Philo Lu April 30, 2024, 12:18 p.m. UTC 
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. IIUC, the
flag can be added to current defination directly, because skb is always
passed from ctx. But I'm not definitely sure about this. Please tell me if
there is any problem. Thanks in advance.

Selftests are expanded with skb dynptr used in tp_btf. They also make sure
that skb dynptr cannot be used in fentry/fexit.

[0]
https://lore.kernel.org/all/20240205121038.41344-1-lulie@linux.alibaba.com/T/

Philo Lu (2):
  bpf: Allow bpf_dynptr_from_skb() for tp_btf
  selftests/bpf: Expand skb dynptr selftests for tp_btf

 net/core/filter.c                             |  3 +-
 .../testing/selftests/bpf/prog_tests/dynptr.c | 36 +++++++++++++++++--
 .../testing/selftests/bpf/progs/dynptr_fail.c | 25 +++++++++++++
 .../selftests/bpf/progs/dynptr_success.c      | 23 ++++++++++++
 4 files changed, 84 insertions(+), 3 deletions(-)

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2.32.0.3.g01195cf9f