1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2021 Facebook */
3 #include "vmlinux.h"
4 #include <bpf/bpf_helpers.h>
5 #define vm_flags vm_start
6 
7 char _license[] SEC("license") = "GPL";
8 
9 struct callback_ctx {
10 	int dummy;
11 };
12 
13 static long write_vma(struct task_struct *task, struct vm_area_struct *vma,
14 		      struct callback_ctx *data)
15 {
16 	/* writing to vma, which is illegal */
17 	vma->vm_start = 0xffffffffff600000;
18 
19 	return 0;
20 }
21 
22 SEC("raw_tp/sys_enter")
23 int handle_getpid(void)
24 {
25 	struct task_struct *task = bpf_get_current_task_btf();
26 	struct callback_ctx data = {};
27 
28 	bpf_find_vma(task, 0, write_vma, &data, 0);
29 	return 0;
30 }
31