* [PATCH] test_kprobes: Add recursed kprobe test case
@ 2023-01-19 15:33 Masami Hiramatsu (Google)
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From: Masami Hiramatsu (Google) @ 2023-01-19 15:33 UTC (permalink / raw
To: linux-trace-kernel, linux-kernel
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
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.
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
lib/test_kprobes.c | 39 +++++++++++++++++++++++++++++++++++++--
1 file changed, 37 insertions(+), 2 deletions(-)
diff --git a/lib/test_kprobes.c b/lib/test_kprobes.c
index 1c95e5719802..0648f7154f5c 100644
--- a/lib/test_kprobes.c
+++ b/lib/test_kprobes.c
@@ -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),
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2023-01-19 15:33 [PATCH] test_kprobes: Add recursed kprobe test case Masami Hiramatsu (Google)
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