// SPDX-License-Identifier: GPL-2.0-or-later
/*
* test_kprobes.c - simple sanity test for k*probes
*
* Copyright IBM Corp. 2008
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/random.h>
#include <kunit/test.h>
#define div_factor 3
static u32 rand1, preh_val, posth_val;
static u32 (*target)(u32 value);
static u32 (*recursed_target)(u32 value);
static u32 (*target2)(u32 value);
static struct kunit *current_test;
static unsigned long (*internal_target)(void);
static unsigned long (*stacktrace_target)(void);
static unsigned long (*stacktrace_driver)(void);
static unsigned long target_return_address[2];
static noinline u32 kprobe_target(u32 value)
{
return (value / div_factor);
}
static noinline u32 kprobe_recursed_target(u32 value)
{
return (value / div_factor);
}
static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
preh_val = recursed_target(rand1);
return 0;
}
static void kp_post_handler(struct kprobe *p, struct pt_regs *regs,
unsigned long flags)
{
u32 expval = recursed_target(rand1);
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, preh_val, expval);
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 void test_kprobe(struct kunit *test)
{
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_kprobe(&kp));
target(rand1);
unregister_kprobe(&kp);
KUNIT_EXPECT_NE(test, 0, preh_val);
KUNIT_EXPECT_NE(test, 0, posth_val);
}
static noinline u32 kprobe_target2(u32 value)
{
return (value / div_factor) + 1;
}
static noinline unsigned long kprobe_stacktrace_internal_target(void)
{
if (!target_return_address[0])
target_return_address[0] = (unsigned long)__builtin_return_address(0);
return target_return_address[0];
}
static noinline unsigned long kprobe_stacktrace_target(void)
{
if (!target_return_address[1])
target_return_address[1] = (unsigned long)__builtin_return_address(0);
if (internal_target)
internal_target();
return target_return_address[1];
}
static noinline unsigned long kprobe_stacktrace_driver(void)
{
if (stacktrace_target)
stacktrace_target();
/* This is for preventing inlining the function */
return (unsigned long)__builtin_return_address(0);
}
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)
{
KUNIT_EXPECT_EQ(current_test, preh_val, (rand1 / div_factor) + 1);
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 void test_kprobes(struct kunit *test)
{
struct kprobe *kps[2] = {&kp, &kp2};
current_test = test;
/* addr and flags should be cleard for reusing kprobe. */
kp.addr = NULL;
kp.flags = 0;
KUNIT_EXPECT_EQ(test, 0, register_kprobes(kps, 2));
preh_val = 0;
posth_val = 0;
target(rand1);
KUNIT_EXPECT_NE(test, 0, preh_val);
KUNIT_EXPECT_NE(test, 0, posth_val);
preh_val = 0;
posth_val = 0;
target2(rand1);
KUNIT_EXPECT_NE(test, 0, preh_val);
KUNIT_EXPECT_NE(test, 0, posth_val);
unregister_kprobes(kps, 2);
}
static struct kprobe kp_missed = {
.symbol_name = "kprobe_recursed_target",
.pre_handler = kp_pre_handler,
.post_handler = kp_post_handler,
};
static void test_kprobe_missed(struct kunit *test)
{
current_test = test;
preh_val = 0;
posth_val = 0;
KUNIT_EXPECT_EQ(test, 0, register_kprobe(&kp_missed));
recursed_target(rand1);
KUNIT_EXPECT_EQ(test, 2, kp_missed.nmissed);
KUNIT_EXPECT_NE(test, 0, preh_val);
KUNIT_EXPECT_NE(test, 0, posth_val);
unregister_kprobe(&kp_missed);
}
#ifdef CONFIG_KRETPROBES
static u32 krph_val;
static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
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);
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, ret, rand1 / div_factor);
KUNIT_EXPECT_NE(current_test, krph_val, 0);
krph_val = rand1;
return 0;
}
static struct kretprobe rp = {
.handler = return_handler,
.entry_handler = entry_handler,
.kp.symbol_name = "kprobe_target"
};
static void test_kretprobe(struct kunit *test)
{
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_kretprobe(&rp));
target(rand1);
unregister_kretprobe(&rp);
KUNIT_EXPECT_EQ(test, krph_val, rand1);
}
static int return_handler2(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long ret = regs_return_value(regs);
KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
KUNIT_EXPECT_NE(current_test, krph_val, 0);
krph_val = rand1;
return 0;
}
static struct kretprobe rp2 = {
.handler = return_handler2,
.entry_handler = entry_handler,
.kp.symbol_name = "kprobe_target2"
};
static void test_kretprobes(struct kunit *test)
{
struct kretprobe *rps[2] = {&rp, &rp2};
current_test = test;
/* addr and flags should be cleard for reusing kprobe. */
rp.kp.addr = NULL;
rp.kp.flags = 0;
KUNIT_EXPECT_EQ(test, 0, register_kretprobes(rps, 2));
krph_val = 0;
target(rand1);
KUNIT_EXPECT_EQ(test, krph_val, rand1);
krph_val = 0;
target2(rand1);
KUNIT_EXPECT_EQ(test, krph_val, rand1);
unregister_kretprobes(rps, 2);
}
#ifdef CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
#define STACK_BUF_SIZE 16
static unsigned long stack_buf[STACK_BUF_SIZE];
static int stacktrace_return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long retval = regs_return_value(regs);
int i, ret;
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, retval, target_return_address[1]);
/*
* Test stacktrace inside the kretprobe handler, this will involves
* kretprobe trampoline, but must include correct return address
* of the target function.
*/
ret = stack_trace_save(stack_buf, STACK_BUF_SIZE, 0);
KUNIT_EXPECT_NE(current_test, ret, 0);
for (i = 0; i < ret; i++) {
if (stack_buf[i] == target_return_address[1])
break;
}
KUNIT_EXPECT_NE(current_test, i, ret);
#if !IS_MODULE(CONFIG_KPROBES_SANITY_TEST)
/*
* Test stacktrace from pt_regs at the return address. Thus the stack
* trace must start from the target return address.
*/
ret = stack_trace_save_regs(regs, stack_buf, STACK_BUF_SIZE, 0);
KUNIT_EXPECT_NE(current_test, ret, 0);
KUNIT_EXPECT_EQ(current_test, stack_buf[0], target_return_address[1]);
#endif
return 0;
}
static struct kretprobe rp3 = {
.handler = stacktrace_return_handler,
.kp.symbol_name = "kprobe_stacktrace_target"
};
static void test_stacktrace_on_kretprobe(struct kunit *test)
{
unsigned long myretaddr = (unsigned long)__builtin_return_address(0);
current_test = test;
rp3.kp.addr = NULL;
rp3.kp.flags = 0;
/*
* Run the stacktrace_driver() to record correct return address in
* stacktrace_target() and ensure stacktrace_driver() call is not
* inlined by checking the return address of stacktrace_driver()
* and the return address of this function is different.
*/
KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver());
KUNIT_ASSERT_EQ(test, 0, register_kretprobe(&rp3));
KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver());
unregister_kretprobe(&rp3);
}
static int stacktrace_internal_return_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
{
unsigned long retval = regs_return_value(regs);
int i, ret;
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, retval, target_return_address[0]);
/*
* Test stacktrace inside the kretprobe handler for nested case.
* The unwinder will find the kretprobe_trampoline address on the
* return address, and kretprobe must solve that.
*/
ret = stack_trace_save(stack_buf, STACK_BUF_SIZE, 0);
KUNIT_EXPECT_NE(current_test, ret, 0);
for (i = 0; i < ret - 1; i++) {
if (stack_buf[i] == target_return_address[0]) {
KUNIT_EXPECT_EQ(current_test, stack_buf[i + 1], target_return_address[1]);
break;
}
}
KUNIT_EXPECT_NE(current_test, i, ret);
#if !IS_MODULE(CONFIG_KPROBES_SANITY_TEST)
/* Ditto for the regs version. */
ret = stack_trace_save_regs(regs, stack_buf, STACK_BUF_SIZE, 0);
KUNIT_EXPECT_NE(current_test, ret, 0);
KUNIT_EXPECT_EQ(current_test, stack_buf[0], target_return_address[0]);
KUNIT_EXPECT_EQ(current_test, stack_buf[1], target_return_address[1]);
#endif
return 0;
}
static struct kretprobe rp4 = {
.handler = stacktrace_internal_return_handler,
.kp.symbol_name = "kprobe_stacktrace_internal_target"
};
static void test_stacktrace_on_nested_kretprobe(struct kunit *test)
{
unsigned long myretaddr = (unsigned long)__builtin_return_address(0);
struct kretprobe *rps[2] = {&rp3, &rp4};
current_test = test;
rp3.kp.addr = NULL;
rp3.kp.flags = 0;
//KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver());
KUNIT_ASSERT_EQ(test, 0, register_kretprobes(rps, 2));
KUNIT_ASSERT_NE(test, myretaddr, stacktrace_driver());
unregister_kretprobes(rps, 2);
}
#endif /* CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE */
#endif /* CONFIG_KRETPROBES */
static int kprobes_test_init(struct kunit *test)
{
target = kprobe_target;
target2 = kprobe_target2;
recursed_target = kprobe_recursed_target;
stacktrace_target = kprobe_stacktrace_target;
internal_target = kprobe_stacktrace_internal_target;
stacktrace_driver = kprobe_stacktrace_driver;
rand1 = get_random_u32_above(div_factor);
return 0;
}
static struct kunit_case kprobes_testcases[] = {
KUNIT_CASE(test_kprobe),
KUNIT_CASE(test_kprobes),
KUNIT_CASE(test_kprobe_missed),
#ifdef CONFIG_KRETPROBES
KUNIT_CASE(test_kretprobe),
KUNIT_CASE(test_kretprobes),
#ifdef CONFIG_ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
KUNIT_CASE(test_stacktrace_on_kretprobe),
KUNIT_CASE(test_stacktrace_on_nested_kretprobe),
#endif
#endif
{}
};
static struct kunit_suite kprobes_test_suite = {
.name = "kprobes_test",
.init = kprobes_test_init,
.test_cases = kprobes_testcases,
};
kunit_test_suites(&kprobes_test_suite);
MODULE_DESCRIPTION("simple sanity test for k*probes");
MODULE_LICENSE("GPL");
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