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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* test_kprobes.c - simple sanity test for *probes
*
* Copyright IBM Corp. 2008
*/
#define pr_fmt(fmt) "Kprobe smoke test: " fmt
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/random.h>
#define div_factor 3
static u32 rand1, preh_val, posth_val;
static int errors, handler_errors, num_tests;
static u32 (*target)(u32 value);
static u32 (*target2)(u32 value);
static noinline u32 kprobe_target(u32 value)
{
return (value / div_factor);
}
static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
if (preemptible()) {
handler_errors++;
pr_err("pre-handler is preemptible\n");
}
preh_val = (rand1 / div_factor);
return 0;
}
static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
if (preemptible()) {
handler_errors++;
pr_err("post-handler is preemptible\n");
}
if (preh_val != (rand1 / div_factor)) {
handler_errors++;
pr_err("incorrect value in post_handler\n");
}
posth_val = preh_val + div_factor;
}
static struct kprobe kp = {
.symbol_name = "kprobe_target",
.pre_handler = kp_pre_handler,
.post_handler = kp_post_handler
};
static int test_kprobe(void)
{
int ret;
ret = register_kprobe(&kp);
if (ret < 0) {
pr_err("register_kprobe returned %d\n", ret);
return ret;
}
ret = target(rand1);
unregister_kprobe(&kp);
if (preh_val == 0) {
pr_err("kprobe pre_handler not called\n");
handler_errors++;
}
if (posth_val == 0) {
pr_err("kprobe post_handler not called\n");
handler_errors++;
}
return 0;
}
static noinline u32 kprobe_target2(u32 value)
{
return (value / div_factor) + 1;
}
static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
{
preh_val = (rand1 / div_factor) + 1;
return 0;
}
static void kp_post_handler2(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
if (preh_val != (rand1 / div_factor) + 1) {
handler_errors++;
pr_err("incorrect value in post_handler2\n");
}
posth_val = preh_val + div_factor;
}
static struct kprobe kp2 = {
.symbol_name = "kprobe_target2",
.pre_handler = kp_pre_handler2,
.post_handler = kp_post_handler2
};
static int test_kprobes(void)
{
int ret;
struct kprobe *kps[2] = {&kp, &kp2};
/* addr and flags should be cleard for reusing kprobe. */
kp.addr = NULL;
kp.flags = 0;
ret = register_kprobes(kps, 2);
if (ret < 0) {
pr_err("register_kprobes returned %d\n", ret);
return ret;
}
preh_val = 0;
posth_val = 0;
ret = target(rand1);
if (preh_val == 0) {
pr_err("kprobe pre_handler not called\n");
handler_errors++;
}
if (posth_val == 0) {
pr_err("kprobe post_handler not called\n");
handler_errors++;
}
preh_val = 0;
posth_val = 0;
ret = target2(rand1);
if (preh_val == 0) {
pr_err("kprobe pre_handler2 not called\n");
handler_errors++;
}
if (posth_val == 0) {
pr_err("kprobe post_handler2 not called\n");
handler_errors++;
}
unregister_kprobes(kps, 2);
return 0;
}
#ifdef CONFIG_KRETPROBES
static u32 krph_val;
static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
if (preemptible()) {
handler_errors++;
pr_err("kretprobe entry handler is preemptible\n");
}
krph_val = (rand1 / div_factor);
return 0;
}
static int return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long ret = regs_return_value(regs);
if (preemptible()) {
handler_errors++;
pr_err("kretprobe return handler is preemptible\n");
}
if (ret != (rand1 / div_factor)) {
handler_errors++;
pr_err("incorrect value in kretprobe handler\n");
}
if (krph_val == 0) {
handler_errors++;
pr_err("call to kretprobe entry handler failed\n");
}
krph_val = rand1;
return 0;
}
static struct kretprobe rp = {
.handler = return_handler,
.entry_handler = entry_handler,
.kp.symbol_name = "kprobe_target"
};
static int test_kretprobe(void)
{
int ret;
ret = register_kretprobe(&rp);
if (ret < 0) {
pr_err("register_kretprobe returned %d\n", ret);
return ret;
}
ret = target(rand1);
unregister_kretprobe(&rp);
if (krph_val != rand1) {
pr_err("kretprobe handler not called\n");
handler_errors++;
}
return 0;
}
static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long ret = regs_return_value(regs);
if (ret != (rand1 / div_factor) + 1) {
handler_errors++;
pr_err("incorrect value in kretprobe handler2\n");
}
if (krph_val == 0) {
handler_errors++;
pr_err("call to kretprobe entry handler failed\n");
}
krph_val = rand1;
return 0;
}
static struct kretprobe rp2 = {
.handler = return_handler2,
.entry_handler = entry_handler,
.kp.symbol_name = "kprobe_target2"
};
static int test_kretprobes(void)
{
int ret;
struct kretprobe *rps[2] = {&rp, &rp2};
/* addr and flags should be cleard for reusing kprobe. */
rp.kp.addr = NULL;
rp.kp.flags = 0;
ret = register_kretprobes(rps, 2);
if (ret < 0) {
pr_err("register_kretprobe returned %d\n", ret);
return ret;
}
krph_val = 0;
ret = target(rand1);
if (krph_val != rand1) {
pr_err("kretprobe handler not called\n");
handler_errors++;
}
krph_val = 0;
ret = target2(rand1);
if (krph_val != rand1) {
pr_err("kretprobe handler2 not called\n");
handler_errors++;
}
unregister_kretprobes(rps, 2);
return 0;
}
#endif /* CONFIG_KRETPROBES */
int init_test_probes(void)
{
int ret;
target = kprobe_target;
target2 = kprobe_target2;
do {
rand1 = prandom_u32();
} while (rand1 <= div_factor);
pr_info("started\n");
num_tests++;
ret = test_kprobe();
if (ret < 0)
errors++;
num_tests++;
ret = test_kprobes();
if (ret < 0)
errors++;
#ifdef CONFIG_KRETPROBES
num_tests++;
ret = test_kretprobe();
if (ret < 0)
errors++;
num_tests++;
ret = test_kretprobes();
if (ret < 0)
errors++;
#endif /* CONFIG_KRETPROBES */
if (errors)
pr_err("BUG: %d out of %d tests failed\n", errors, num_tests);
else if (handler_errors)
pr_err("BUG: %d error(s) running handlers\n", handler_errors);
else
pr_info("passed successfully\n");
return 0;
}