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// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
struct map_elem {
struct bpf_timer timer;
struct bpf_spin_lock lock;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, struct map_elem);
} amap SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_HASH);
__uint(max_entries, 1);
__type(key, int);
__type(value, struct map_elem);
} hmap SEC(".maps");
int pid = 0;
int crash_map = 0; /* 0 for amap, 1 for hmap */
SEC("fentry/do_nanosleep")
int sys_enter(void *ctx)
{
struct map_elem *e, value = {};
void *map = crash_map ? (void *)&hmap : (void *)&amap;
if (bpf_get_current_task_btf()->tgid != pid)
return 0;
*(void **)&value = (void *)0xdeadcaf3;
bpf_map_update_elem(map, &(int){0}, &value, 0);
/* For array map, doing bpf_map_update_elem will do a
* check_and_free_timer_in_array, which will trigger the crash if timer
* pointer was overwritten, for hmap we need to use bpf_timer_cancel.
*/
if (crash_map == 1) {
e = bpf_map_lookup_elem(map, &(int){0});
if (!e)
return 0;
bpf_timer_cancel(&e->timer);
}
return 0;
}
char _license[] SEC("license") = "GPL";
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