[PATCH] test_kprobes: Add recursed kprobe test case
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From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Date: 2023-01-20 04:28:53
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lkml
Subsystem:
library code, the rest · Maintainers:
Andrew Morton, Linus Torvalds
Landed in mainline as 1fcd09fd4f84 on 2023-02-20.
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),