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 Signed-off-by: Leon Hwang --- include/linux/bpf.h | 2 +- kernel/bpf/btf.c | 8 ++++---- 2 files changed, 5 insertions(+), 5 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 41f776071ff5..42242e238757 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1113,7 +1113,7 @@ struct bpf_prog_offload { */ #define MAX_BPF_FUNC_REG_ARGS 5 -/* The argument is a structure. */ +/* The argument is a structure or a union. */ #define BTF_FMODEL_STRUCT_ARG BIT(0) /* The argument is signed. */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 64739308902f..bfd83e9e7979 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6762,7 +6762,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, /* skip modifiers */ while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); - if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t)) + if (btf_type_is_small_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t)) /* accessing a scalar */ return true; if (!btf_type_is_ptr(t)) { @@ -7334,7 +7334,7 @@ static int __get_type_size(struct btf *btf, u32 btf_id, if (btf_type_is_ptr(t)) /* kernel size of pointer. Not BPF's size of pointer*/ return sizeof(void *); - if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t)) + if (btf_type_is_int(t) || btf_is_any_enum(t) || btf_type_is_struct(t)) return t->size; return -EINVAL; } @@ -7343,7 +7343,7 @@ static u8 __get_type_fmodel_flags(const struct btf_type *t) { u8 flags = 0; - if (__btf_type_is_struct(t)) + if (btf_type_is_struct(t)) flags |= BTF_FMODEL_STRUCT_ARG; if (btf_type_is_signed_int(t)) flags |= BTF_FMODEL_SIGNED_ARG; @@ -7384,7 +7384,7 @@ int btf_distill_func_proto(struct bpf_verifier_log *log, return -EINVAL; } ret = __get_type_size(btf, func->type, &t); - if (ret < 0 || __btf_type_is_struct(t)) { + if (ret < 0 || btf_type_is_struct(t)) { bpf_log(log, "The function %s return type %s is unsupported.\n", tname, btf_type_str(t)); -- 2.51.0