Commit 1fcd09fd authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google)
Browse files

test_kprobes: Add recursed kprobe test case 

Add a recursed kprobe test case to the KUnit test module for kprobes.
This will probe a function which is called from the pre_handler and
post_handler itself. If the kprobe is correctly implemented, the recursed
kprobe handlers will be skipped and the number of skipped kprobe will
be counted on kprobe::nmissed.

Link: https://lore.kernel.org/all/167414238758.2301956.258548940194352895.stgit@devnote3/



Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
parent 8478cca1

lib/test_kprobes.c

+37 −2
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 


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;
@@ -27,18 +28,27 @@ 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 = (rand1 / div_factor);



	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, (rand1 / div_factor));

	KUNIT_EXPECT_EQ(current_test, preh_val, expval);



	posth_val = preh_val + div_factor;

}
@@ -136,6 +146,29 @@ static void test_kprobes(struct kunit *test) 
	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;
@@ -336,6 +369,7 @@ 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;
@@ -346,6 +380,7 @@ static int kprobes_test_init(struct kunit *test) 
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),