diff options
Diffstat (limited to 'lib/test_kprobes.c')
| -rw-r--r-- | lib/test_kprobes.c | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/lib/test_kprobes.c b/lib/test_kprobes.c new file mode 100644 index 000000000000..0648f7154f5c --- /dev/null +++ b/lib/test_kprobes.c @@ -0,0 +1,403 @@ +// 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"); |