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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include "task_kfunc_common.h"
char _license[] SEC("license") = "GPL";
int err, pid;
/* Prototype for all of the program trace events below:
*
* TRACE_EVENT(task_newtask,
* TP_PROTO(struct task_struct *p, u64 clone_flags)
*/
static bool is_test_kfunc_task(void)
{
int cur_pid = bpf_get_current_pid_tgid() >> 32;
return pid == cur_pid;
}
static int test_acquire_release(struct task_struct *task)
{
struct task_struct *acquired;
acquired = bpf_task_acquire(task);
bpf_task_release(acquired);
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_acquire_release_argument, struct task_struct *task, u64 clone_flags)
{
if (!is_test_kfunc_task())
return 0;
return test_acquire_release(task);
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_acquire_release_current, struct task_struct *task, u64 clone_flags)
{
if (!is_test_kfunc_task())
return 0;
return test_acquire_release(bpf_get_current_task_btf());
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_acquire_leave_in_map, struct task_struct *task, u64 clone_flags)
{
long status;
if (!is_test_kfunc_task())
return 0;
status = tasks_kfunc_map_insert(task);
if (status)
err = 1;
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_xchg_release, struct task_struct *task, u64 clone_flags)
{
struct task_struct *kptr;
struct __tasks_kfunc_map_value *v;
long status;
if (!is_test_kfunc_task())
return 0;
status = tasks_kfunc_map_insert(task);
if (status) {
err = 1;
return 0;
}
v = tasks_kfunc_map_value_lookup(task);
if (!v) {
err = 2;
return 0;
}
kptr = bpf_kptr_xchg(&v->task, NULL);
if (!kptr) {
err = 3;
return 0;
}
bpf_task_release(kptr);
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_get_release, struct task_struct *task, u64 clone_flags)
{
struct task_struct *kptr;
struct __tasks_kfunc_map_value *v;
long status;
if (!is_test_kfunc_task())
return 0;
status = tasks_kfunc_map_insert(task);
if (status) {
err = 1;
return 0;
}
v = tasks_kfunc_map_value_lookup(task);
if (!v) {
err = 2;
return 0;
}
kptr = bpf_task_kptr_get(&v->task);
if (kptr) {
/* Until we resolve the issues with using task->rcu_users, we
* expect bpf_task_kptr_get() to return a NULL task. See the
* comment at the definition of bpf_task_acquire_not_zero() for
* more details.
*/
bpf_task_release(kptr);
err = 3;
return 0;
}
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_current_acquire_release, struct task_struct *task, u64 clone_flags)
{
struct task_struct *current, *acquired;
if (!is_test_kfunc_task())
return 0;
current = bpf_get_current_task_btf();
acquired = bpf_task_acquire(current);
bpf_task_release(acquired);
return 0;
}
static void lookup_compare_pid(const struct task_struct *p)
{
struct task_struct *acquired;
acquired = bpf_task_from_pid(p->pid);
if (!acquired) {
err = 1;
return;
}
if (acquired->pid != p->pid)
err = 2;
bpf_task_release(acquired);
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_from_pid_arg, struct task_struct *task, u64 clone_flags)
{
struct task_struct *acquired;
if (!is_test_kfunc_task())
return 0;
lookup_compare_pid(task);
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_from_pid_current, struct task_struct *task, u64 clone_flags)
{
struct task_struct *current, *acquired;
if (!is_test_kfunc_task())
return 0;
lookup_compare_pid(bpf_get_current_task_btf());
return 0;
}
static int is_pid_lookup_valid(s32 pid)
{
struct task_struct *acquired;
acquired = bpf_task_from_pid(pid);
if (acquired) {
bpf_task_release(acquired);
return 1;
}
return 0;
}
SEC("tp_btf/task_newtask")
int BPF_PROG(test_task_from_pid_invalid, struct task_struct *task, u64 clone_flags)
{
struct task_struct *acquired;
if (!is_test_kfunc_task())
return 0;
if (is_pid_lookup_valid(-1)) {
err = 1;
return 0;
}
if (is_pid_lookup_valid(0xcafef00d)) {
err = 2;
return 0;
}
return 0;
}
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