bpf: Allow union argument in trampoline based programs

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Currently, functions with 'union' arguments cannot be traced with
fentry/fexit:

bpftrace -e 'fentry:release_pages { exit(); }' -v

The function release_pages arg0 type UNION is unsupported.

The type of the 'release_pages' arg0 is defined as:

typedef union {
	struct page **pages;
	struct folio **folios;
	struct encoded_page **encoded_pages;
} release_pages_arg __attribute__ ((__transparent_union__));

This patch relaxes the restriction by allowing function arguments of type
'union' to be traced in verifier.

Reviewed-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20250919044110.23729-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

...

This commit is contained in:

Leon Hwang 2025-09-19 12:41:09 +08:00 • committed by Alexei Starovoitov

parent 2383e45f1d

commit ccb4f5d91e

2 changed files with 5 additions and 5 deletions

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2

include/linux/bpf.h

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8

kernel/bpf/btf.c

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