linux-kernel - [PATCH bpf-next v4 0/2] bpf: Allow access to const void pointer arguments in tracing programs

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Message-ID: <20250423121329.3163461-1-mannkafai@gmail.com>
Date: Wed, 23 Apr 2025 20:13:27 +0800
From: KaFai Wan <mannkafai@...il.com>
To: alexei.starovoitov@...il.com,
	martin.lau@...ux.dev,
	ast@...nel.org,
	daniel@...earbox.net,
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Cc: bpf@...r.kernel.org,
	linux-kernel@...r.kernel.org,
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	leon.hwang@...ux.dev,
	KaFai Wan <mannkafai@...il.com>
Subject: [PATCH bpf-next v4 0/2] bpf: Allow access to const void pointer arguments in tracing programs

If we try to access argument which is pointer to const void, it's an 
UNKNOWN type, verifier will fail to load.

Use is_void_or_int_ptr to check if type is void or int pointer. 
Add a selftest to check it.

---
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                                    | 13 +++----------
 net/bpf/test_run.c                                  |  8 +++++++-
 .../selftests/bpf/progs/verifier_btf_ctx_access.c   | 12 ++++++++++++
 3 files changed, 22 insertions(+), 11 deletions(-)

Changelog:
v3->v4: Addressed comments from Alexei Starovoitov
- change SOB to match From email address
- add Acked-by from jirka
Details in here:
https://lore.kernel.org/all/20250417151548.1276279-1-kafai.wan@hotmail.com/

v2->v3: Addressed comments from jirka
- remove duplicate checks for void pointer
Details in here:
https://lore.kernel.org/bpf/20250416161756.1079178-1-kafai.wan@hotmail.com/

v1->v2: Addressed comments from jirka
- use btf_type_is_void to check if type is void
- merge is_void_ptr and is_int_ptr to is_void_or_int_ptr
- fix selftests
Details in here:
https://lore.kernel.org/all/20250412170626.3638516-1-kafai.wan@hotmail.com/

-- 
2.43.0