// 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 576. Too large") 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 608. Too large") 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";