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