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bpf: Simplify reg0 marking for the list kfuncs that return a bpf_list_node pointer

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The next patch will add bpf_list_{front,back} kfuncs to peek the head
and tail of a list. Both of them will return a 'struct bpf_list_node *'.

Follow the earlier change for rbtree, this patch checks the
return btf type is a 'struct bpf_list_node' pointer instead
of checking each kfuncs individually to decide if
mark_reg_graph_node should be called. This will make
the bpf_list_{front,back} kfunc addition easier in
the later patch.

Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250506015857.817950-7-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Martin KaFai Lau
2025-05-05 18:58:53 -07:00
committed by Alexei Starovoitov
parent 47ada65c5c
commit 3fab84f00d
1 changed files with 6 additions and 2 deletions
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8
kernel/bpf/verifier.c
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@@ -11992,6 +11992,11 @@ static bool is_rbtree_node_type(const struct btf_type *t)
return t == btf_type_by_id(btf_vmlinux, kf_arg_btf_ids[KF_ARG_RB_NODE_ID]);
}
static bool is_list_node_type(const struct btf_type *t)
{
return t == btf_type_by_id(btf_vmlinux, kf_arg_btf_ids[KF_ARG_LIST_NODE_ID]);
}
static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
const struct btf_param *arg)
{
@@ -13764,8 +13769,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
insn_aux->kptr_struct_meta =
btf_find_struct_meta(meta.arg_btf,
meta.arg_btf_id);
} else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
} else if (is_list_node_type(ptr_type)) {
struct btf_field *field = meta.arg_list_head.field;
mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);