// SPDX-License-Identifier: GPL-2.0-or-later /* * test_kprobes.c - simple sanity test for *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_LICENSE("GPL");