libbpf: Fix USDT SIB argument handling causing unrecognized register error

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[ Upstream commit 758acb9ccf ]

On x86-64, USDT arguments can be specified using Scale-Index-Base (SIB)
addressing, e.g. "1@-96(%rbp,%rax,8)". The current USDT implementation
in libbpf cannot parse this format, causing `bpf_program__attach_usdt()`
to fail with -ENOENT (unrecognized register).

This patch fixes this by implementing the necessary changes:
- add correct handling for SIB-addressed arguments in `bpf_usdt_arg`.
- add adaptive support to `__bpf_usdt_arg_type` and
  `__bpf_usdt_arg_spec` to represent SIB addressing parameters.

Signed-off-by: Jiawei Zhao <phoenix500526@163.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250827053128.1301287-2-phoenix500526@163.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

This commit is contained in:

Jiawei Zhao 2025-08-27 05:31:27 +00:00 • committed by Greg Kroah-Hartman

parent 59b95f18cf

commit eadee37283

2 changed files with 99 additions and 7 deletions

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44

tools/lib/bpf/usdt.bpf.h

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62

tools/lib/bpf/usdt.c

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