linux/lib/test_fprobe.c
Masami Hiramatsu (Google) cb16330d12 fprobe: Pass return address to the handlers
Pass return address as 'ret_ip' to the fprobe entry and return handlers
so that the fprobe user handler can get the reutrn address without
analyzing arch-dependent pt_regs.

Link: https://lore.kernel.org/all/168507467664.913472.11642316698862778600.stgit@mhiramat.roam.corp.google.com/

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
2023-06-06 21:39:55 +09:00

276 lines
6.9 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* test_fprobe.c - simple sanity test for fprobe
*/
#include <linux/kernel.h>
#include <linux/fprobe.h>
#include <linux/random.h>
#include <kunit/test.h>
#define div_factor 3
static struct kunit *current_test;
static u32 rand1, entry_val, exit_val;
/* Use indirect calls to avoid inlining the target functions */
static u32 (*target)(u32 value);
static u32 (*target2)(u32 value);
static u32 (*target_nest)(u32 value, u32 (*nest)(u32));
static unsigned long target_ip;
static unsigned long target2_ip;
static unsigned long target_nest_ip;
static int entry_return_value;
static noinline u32 fprobe_selftest_target(u32 value)
{
return (value / div_factor);
}
static noinline u32 fprobe_selftest_target2(u32 value)
{
return (value / div_factor) + 1;
}
static noinline u32 fprobe_selftest_nest_target(u32 value, u32 (*nest)(u32))
{
return nest(value + 2);
}
static notrace int fp_entry_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
/* This can be called on the fprobe_selftest_target and the fprobe_selftest_target2 */
if (ip != target_ip)
KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
entry_val = (rand1 / div_factor);
if (fp->entry_data_size) {
KUNIT_EXPECT_NOT_NULL(current_test, data);
if (data)
*(u32 *)data = entry_val;
} else
KUNIT_EXPECT_NULL(current_test, data);
return entry_return_value;
}
static notrace void fp_exit_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
unsigned long ret = regs_return_value(regs);
KUNIT_EXPECT_FALSE(current_test, preemptible());
if (ip != target_ip) {
KUNIT_EXPECT_EQ(current_test, ip, target2_ip);
KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor) + 1);
} else
KUNIT_EXPECT_EQ(current_test, ret, (rand1 / div_factor));
KUNIT_EXPECT_EQ(current_test, entry_val, (rand1 / div_factor));
exit_val = entry_val + div_factor;
if (fp->entry_data_size) {
KUNIT_EXPECT_NOT_NULL(current_test, data);
if (data)
KUNIT_EXPECT_EQ(current_test, *(u32 *)data, entry_val);
} else
KUNIT_EXPECT_NULL(current_test, data);
}
static notrace int nest_entry_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
return 0;
}
static notrace void nest_exit_handler(struct fprobe *fp, unsigned long ip,
unsigned long ret_ip,
struct pt_regs *regs, void *data)
{
KUNIT_EXPECT_FALSE(current_test, preemptible());
KUNIT_EXPECT_EQ(current_test, ip, target_nest_ip);
}
/* Test entry only (no rethook) */
static void test_fprobe_entry(struct kunit *test)
{
struct fprobe fp_entry = {
.entry_handler = fp_entry_handler,
};
current_test = test;
/* Before register, unregister should be failed. */
KUNIT_EXPECT_NE(test, 0, unregister_fprobe(&fp_entry));
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp_entry, "fprobe_selftest_target*", NULL));
entry_val = 0;
exit_val = 0;
target(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, 0, exit_val);
entry_val = 0;
exit_val = 0;
target2(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, 0, exit_val);
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp_entry));
}
static void test_fprobe(struct kunit *test)
{
struct fprobe fp = {
.entry_handler = fp_entry_handler,
.exit_handler = fp_exit_handler,
};
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target*", NULL));
entry_val = 0;
exit_val = 0;
target(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
entry_val = 0;
exit_val = 0;
target2(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
}
static void test_fprobe_syms(struct kunit *test)
{
static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_target2"};
struct fprobe fp = {
.entry_handler = fp_entry_handler,
.exit_handler = fp_exit_handler,
};
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
entry_val = 0;
exit_val = 0;
target(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
entry_val = 0;
exit_val = 0;
target2(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, entry_val + div_factor, exit_val);
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
}
/* Test private entry_data */
static void test_fprobe_data(struct kunit *test)
{
struct fprobe fp = {
.entry_handler = fp_entry_handler,
.exit_handler = fp_exit_handler,
.entry_data_size = sizeof(u32),
};
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
target(rand1);
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
}
/* Test nr_maxactive */
static void test_fprobe_nest(struct kunit *test)
{
static const char *syms[] = {"fprobe_selftest_target", "fprobe_selftest_nest_target"};
struct fprobe fp = {
.entry_handler = nest_entry_handler,
.exit_handler = nest_exit_handler,
.nr_maxactive = 1,
};
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_fprobe_syms(&fp, syms, 2));
target_nest(rand1, target);
KUNIT_EXPECT_EQ(test, 1, fp.nmissed);
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
}
static void test_fprobe_skip(struct kunit *test)
{
struct fprobe fp = {
.entry_handler = fp_entry_handler,
.exit_handler = fp_exit_handler,
};
current_test = test;
KUNIT_EXPECT_EQ(test, 0, register_fprobe(&fp, "fprobe_selftest_target", NULL));
entry_return_value = 1;
entry_val = 0;
exit_val = 0;
target(rand1);
KUNIT_EXPECT_NE(test, 0, entry_val);
KUNIT_EXPECT_EQ(test, 0, exit_val);
KUNIT_EXPECT_EQ(test, 0, fp.nmissed);
entry_return_value = 0;
KUNIT_EXPECT_EQ(test, 0, unregister_fprobe(&fp));
}
static unsigned long get_ftrace_location(void *func)
{
unsigned long size, addr = (unsigned long)func;
if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size)
return 0;
return ftrace_location_range(addr, addr + size - 1);
}
static int fprobe_test_init(struct kunit *test)
{
rand1 = get_random_u32_above(div_factor);
target = fprobe_selftest_target;
target2 = fprobe_selftest_target2;
target_nest = fprobe_selftest_nest_target;
target_ip = get_ftrace_location(target);
target2_ip = get_ftrace_location(target2);
target_nest_ip = get_ftrace_location(target_nest);
return 0;
}
static struct kunit_case fprobe_testcases[] = {
KUNIT_CASE(test_fprobe_entry),
KUNIT_CASE(test_fprobe),
KUNIT_CASE(test_fprobe_syms),
KUNIT_CASE(test_fprobe_data),
KUNIT_CASE(test_fprobe_nest),
KUNIT_CASE(test_fprobe_skip),
{}
};
static struct kunit_suite fprobe_test_suite = {
.name = "fprobe_test",
.init = fprobe_test_init,
.test_cases = fprobe_testcases,
};
kunit_test_suites(&fprobe_test_suite);