From: Martin KaFai Lau Date: Tue, 6 May 2025 01:58:53 +0000 (-0700) Subject: bpf: Simplify reg0 marking for the list kfuncs that return a bpf_list_node pointer X-Git-Tag: v6.16-rc1~131^2~41^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3fab84f00d3274e1fd19054a409a9c804261e4b9;p=thirdparty%2Flinux.git bpf: Simplify reg0 marking for the list kfuncs that return a bpf_list_node pointer 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 Signed-off-by: Martin KaFai Lau Link: https://lore.kernel.org/r/20250506015857.817950-7-martin.lau@linux.dev Signed-off-by: Alexei Starovoitov --- diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 9093a351b0b38..acb2f44316ccc 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -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);