// SPDX-License-Identifier: GPL-2.0#include <vmlinux.h>#include <bpf/bpf_helpers.h> #include "bpf_misc.h" struct hmap_elem {	struct bpf_timer timer;}; struct {	__uint(type, BPF_MAP_TYPE_HASH);	__uint(max_entries, 64);	__type(key, int);	__type(value, struct hmap_elem);} hmap SEC(".maps"); __attribute__((noinline))static int timer_cb(void *map, int *key, struct bpf_timer *timer){	volatile char buf[256] = {};	return buf[69];} __attribute__((noinline))static int bad_timer_cb(void *map, int *key, struct bpf_timer *timer){	volatile char buf[300] = {};	return buf[255] + timer_cb(NULL, NULL, NULL);} SEC("tc")__failure __msg("combined stack size of 2 calls is")int pseudo_call_check(struct __sk_buff *ctx){	struct hmap_elem *elem;	volatile char buf[256] = {}; 	elem = bpf_map_lookup_elem(&hmap, &(int){0});	if (!elem)		return 0; 	timer_cb(NULL, NULL, NULL);	return bpf_timer_set_callback(&elem->timer, timer_cb) + buf[0];} SEC("tc")__failure __msg("combined stack size of 2 calls is")int async_call_root_check(struct __sk_buff *ctx){	struct hmap_elem *elem;	volatile char buf[256] = {}; 	elem = bpf_map_lookup_elem(&hmap, &(int){0});	if (!elem)		return 0; 	return bpf_timer_set_callback(&elem->timer, bad_timer_cb) + buf[0];} char _license[] SEC("license") = "GPL";