diff options
| -rw-r--r-- | arch/Kconfig | 8 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | kernel/test_kprobes.c | 162 |
3 files changed, 171 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 8df1c7102643..8378f83b462c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -191,6 +191,14 @@ config HAVE_OPTPROBES config HAVE_KPROBES_ON_FTRACE bool +config ARCH_CORRECT_STACKTRACE_ON_KRETPROBE + bool + help + Since kretprobes modifies return address on the stack, the + stacktrace may see the kretprobe trampoline address instead + of correct one. If the architecture stacktrace code and + unwinder can adjust such entries, select this configuration. + config HAVE_FUNCTION_ERROR_INJECTION bool diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index e39e2bd6acc5..cc9ba6798848 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -61,6 +61,7 @@ config X86 select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI select ARCH_32BIT_OFF_T if X86_32 select ARCH_CLOCKSOURCE_INIT + select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE select ARCH_ENABLE_HUGEPAGE_MIGRATION if X86_64 && HUGETLB_PAGE && MIGRATION select ARCH_ENABLE_MEMORY_HOTPLUG if X86_64 || (X86_32 && HIGHMEM) select ARCH_ENABLE_MEMORY_HOTREMOVE if MEMORY_HOTPLUG diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c index e78f18144145..a5edc2ebc947 100644 --- a/kernel/test_kprobes.c +++ b/kernel/test_kprobes.c @@ -17,6 +17,11 @@ static u32 (*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); @@ -58,6 +63,33 @@ 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; @@ -175,12 +207,138 @@ static void test_kretprobes(struct kunit *test) 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; + stacktrace_target = kprobe_stacktrace_target; + internal_target = kprobe_stacktrace_internal_target; + stacktrace_driver = kprobe_stacktrace_driver; do { rand1 = prandom_u32(); @@ -194,6 +352,10 @@ static struct kunit_case kprobes_testcases[] = { #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 {} }; |