[PATCH 1/8] kprobes: convert tests to kunit

Masami Hiramatsu
2021-10-08T12:28:29Z

From: Sven Schnelle <svens@linux.ibm.com>

This converts the kprobes testcases to use the kunit framework.
It adds a dependency on CONFIG_KUNIT, and the output will change
to TAP:

TAP version 14
1..1
# Subtest: kprobes_test
1..4
random: crng init done
ok 1 - test_kprobe
ok 2 - test_kprobes
ok 3 - test_kretprobe
ok 4 - test_kretprobes
ok 1 - kprobes_test

Note that the kprobes testcases are no longer run immediately after
kprobes initialization, but as a late initcall when kunit is
initialized. kprobes itself is initialized with an early initcall,
so the order is still correct.

Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
kernel/kprobes.c | 3 -
kernel/test_kprobes.c | 222 +++++++++++++------------------------------------
lib/Kconfig.debug | 3 -
3 files changed, 61 insertions(+), 167 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index b62af9fc3607..4676627cb066 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -2581,9 +2581,6 @@ static int __init init_kprobes(void)
err = register_module_notifier(&kprobe_module_nb);

kprobes_initialized = (err == 0);
-
- if (!err)
- init_test_probes();
return err;
}
early_initcall(init_kprobes);
diff --git a/kernel/test_kprobes.c b/kernel/test_kprobes.c
index 76c997fdbc9d..e78f18144145 100644
--- a/kernel/test_kprobes.c
+++ b/kernel/test_kprobes.c
@@ -5,18 +5,17 @@
* Copyright IBM Corp. 2008
*/

-#define pr_fmt(fmt) "Kprobe smoke test: " fmt
-
#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 int errors, handler_errors, num_tests;
static u32 (*target)(u32 value);
static u32 (*target2)(u32 value);
+static struct kunit *current_test;

static noinline u32 kprobe_target(u32 value)
{
@@ -25,10 +24,7 @@ static noinline u32 kprobe_target(u32 value)

static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
{
- if (preemptible()) {
- handler_errors++;
- pr_err("pre-handler is preemptible\n");
- }
+ KUNIT_EXPECT_FALSE(current_test, preemptible());
preh_val = (rand1 / div_factor);
return 0;
}
@@ -36,14 +32,8 @@ static int kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
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");
- }
+ KUNIT_EXPECT_FALSE(current_test, preemptible());
+ KUNIT_EXPECT_EQ(current_test, preh_val, (rand1 / div_factor));
posth_val = preh_val + div_factor;
}

@@ -53,30 +43,14 @@ static struct kprobe kp = {
.post_handler = kp_post_handler
};

-static int test_kprobe(void)
+static void test_kprobe(struct kunit *test)
{
- int ret;
-
- ret = register_kprobe(&kp);
- if (ret < 0) {
- pr_err("register_kprobe returned %d\n", ret);
- return ret;
- }
-
- ret = target(rand1);
+ current_test = test;
+ KUNIT_EXPECT_EQ(test, 0, register_kprobe(&kp));
+ 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;
+ KUNIT_EXPECT_NE(test, 0, preh_val);
+ KUNIT_EXPECT_NE(test, 0, posth_val);
}

static noinline u32 kprobe_target2(u32 value)
@@ -93,10 +67,7 @@ static int kp_pre_handler2(struct kprobe *p, struct pt_regs *regs)
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");
- }
+ KUNIT_EXPECT_EQ(current_test, preh_val, (rand1 / div_factor) + 1);
posth_val = preh_val + div_factor;
}

@@ -106,51 +77,31 @@ static struct kprobe kp2 = {
.post_handler = kp_post_handler2
};

-static int test_kprobes(void)
+static void test_kprobes(struct kunit *test)
{
- int ret;
struct kprobe *kps[2] = {&kp, &kp2};

+ current_test = test;
+
/* 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;
- }

+ KUNIT_EXPECT_EQ(test, 0, register_kprobes(kps, 2));
preh_val = 0;
posth_val = 0;
- ret = target(rand1);
+ 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++;
- }
+ KUNIT_EXPECT_NE(test, 0, preh_val);
+ KUNIT_EXPECT_NE(test, 0, posth_val);

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++;
- }
+ target2(rand1);

+ KUNIT_EXPECT_NE(test, 0, preh_val);
+ KUNIT_EXPECT_NE(test, 0, posth_val);
unregister_kprobes(kps, 2);
- return 0;
-
}

#ifdef CONFIG_KRETPROBES
@@ -158,10 +109,7 @@ 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");
- }
+ KUNIT_EXPECT_FALSE(current_test, preemptible());
krph_val = (rand1 / div_factor);
return 0;
}
@@ -170,19 +118,9 @@ 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");
- }
-
+ 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;
}
@@ -193,39 +131,21 @@ static struct kretprobe rp = {
.kp.symbol_name = "kprobe_target"
};

-static int test_kretprobe(void)
+static void test_kretprobe(struct kunit *test)
{
- int ret;
-
- ret = register_kretprobe(&rp);
- if (ret < 0) {
- pr_err("register_kretprobe returned %d\n", ret);
- return ret;
- }
-
- ret = target(rand1);
+ current_test = test;
+ KUNIT_EXPECT_EQ(test, 0, register_kretprobe(&rp));
+ target(rand1);
unregister_kretprobe(&rp);
- if (krph_val != rand1) {
- pr_err("kretprobe handler not called\n");
- handler_errors++;
- }
-
- return 0;
+ 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);

- 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");
- }
-
+ KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
+ KUNIT_EXPECT_NE(current_test, krph_val, 0);
krph_val = rand1;
return 0;
}
@@ -236,78 +156,54 @@ static struct kretprobe rp2 = {
.kp.symbol_name = "kprobe_target2"
};

-static int test_kretprobes(void)
+static void test_kretprobes(struct kunit *test)
{
- int ret;
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;
- ret = register_kretprobes(rps, 2);
- if (ret < 0) {
- pr_err("register_kretprobe returned %d\n", ret);
- return ret;
- }
+ KUNIT_EXPECT_EQ(test, 0, register_kretprobes(rps, 2));

krph_val = 0;
- ret = target(rand1);
- if (krph_val != rand1) {
- pr_err("kretprobe handler not called\n");
- handler_errors++;
- }
+ target(rand1);
+ KUNIT_EXPECT_EQ(test, krph_val, rand1);

krph_val = 0;
- ret = target2(rand1);
- if (krph_val != rand1) {
- pr_err("kretprobe handler2 not called\n");
- handler_errors++;
- }
+ target2(rand1);
+ KUNIT_EXPECT_EQ(test, krph_val, rand1);
unregister_kretprobes(rps, 2);
- return 0;
}
#endif /* CONFIG_KRETPROBES */

-int init_test_probes(void)
+static int kprobes_test_init(struct kunit *test)
{
- int ret;
-
target = kprobe_target;
target2 = kprobe_target2;

do {
rand1 = prandom_u32();
} while (rand1 <= div_factor);
+ return 0;
+}

- pr_info("started\n");
- num_tests++;
- ret = test_kprobe();
- if (ret < 0)
- errors++;
-
- num_tests++;
- ret = test_kprobes();
- if (ret < 0)
- errors++;
-
+static struct kunit_case kprobes_testcases[] = {
+ KUNIT_CASE(test_kprobe),
+ KUNIT_CASE(test_kprobes),
#ifdef CONFIG_KRETPROBES
- num_tests++;
- ret = test_kretprobe();
- if (ret < 0)
- errors++;
-
- num_tests++;
- ret = test_kretprobes();
- if (ret < 0)
- errors++;
-#endif /* CONFIG_KRETPROBES */
+ KUNIT_CASE(test_kretprobe),
+ KUNIT_CASE(test_kretprobes),
+#endif
+ {}
+};

- 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");
+static struct kunit_suite kprobes_test_suite = {
+ .name = "kprobes_test",
+ .init = kprobes_test_init,
+ .test_cases = kprobes_testcases,
+};

- return 0;
-}
+kunit_test_suites(&kprobes_test_suite);
+
+MODULE_LICENSE("GPL");
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2a9b6dcdac4f..6ceb11a43e4c 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2080,9 +2080,10 @@ config TEST_DIV64
If unsure, say N.

config KPROBES_SANITY_TEST
- bool "Kprobes sanity tests"
+ tristate "Kprobes sanity tests"
depends on DEBUG_KERNEL
depends on KPROBES
+ depends on KUNIT
help
This option provides for testing basic kprobes functionality on
boot. Samples of kprobe and kretprobe are inserted and