kernel/kallsyms_selftest.c - linux/kernel/git/dhowells/linux-fs - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Test the function and performance of kallsyms
  *
  * Copyright (C) Huawei Technologies Co., Ltd., 2022
  *
  * Authors: Zhen Lei <thunder.leizhen@huawei.com> Huawei
  */

 #define pr_fmt(fmt) "kallsyms_selftest: " fmt

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kallsyms.h>
 #include <linux/random.h>
 #include <linux/sched/clock.h>
 #include <linux/kthread.h>
 #include <linux/vmalloc.h>

 #include "kallsyms_internal.h"
 #include "kallsyms_selftest.h"


 #define MAX_NUM_OF_RECORDS		64

 struct test_stat {
 	int min;
 	int max;
 	int save_cnt;
 	int real_cnt;
 	int perf;
 	u64 sum;
 	char *name;
 	unsigned long addr;
 	unsigned long addrs[MAX_NUM_OF_RECORDS];
 };

 struct test_item {
 	char *name;
 	unsigned long addr;
 };

 #define ITEM_FUNC(s)				\
 	{					\
 		.name = #s,			\
 		.addr = (unsigned long)s,	\
 	}

 #define ITEM_DATA(s)				\
 	{					\
 		.name = #s,			\
 		.addr = (unsigned long)&s,	\
 	}


 static int kallsyms_test_var_bss_static;
 static int kallsyms_test_var_data_static = 1;
 int kallsyms_test_var_bss;
 int kallsyms_test_var_data = 1;

 static int kallsyms_test_func_static(void)
 {
 	kallsyms_test_var_bss_static++;
 	kallsyms_test_var_data_static++;

 	return 0;
 }

 int kallsyms_test_func(void)
 {
 	return kallsyms_test_func_static();
 }

 __weak int kallsyms_test_func_weak(void)
 {
 	kallsyms_test_var_bss++;
 	kallsyms_test_var_data++;
 	return 0;
 }

 static struct test_item test_items[] = {
 	ITEM_FUNC(kallsyms_test_func_static),
 	ITEM_FUNC(kallsyms_test_func),
 	ITEM_FUNC(kallsyms_test_func_weak),
 	ITEM_FUNC(vmalloc),
 	ITEM_FUNC(vfree),
 #ifdef CONFIG_KALLSYMS_ALL
 	ITEM_DATA(kallsyms_test_var_bss_static),
 	ITEM_DATA(kallsyms_test_var_data_static),
 	ITEM_DATA(kallsyms_test_var_bss),
 	ITEM_DATA(kallsyms_test_var_data),
 	ITEM_DATA(vmap_area_list),
 #endif
 };

 static char stub_name[KSYM_NAME_LEN];

 static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr)
 {
 	*(u32 *)data += strlen(name);

 	return 0;
 }

 static void test_kallsyms_compression_ratio(void)
 {
 	u32 pos, off, len, num;
 	u32 ratio, total_size, total_len = 0;

 	kallsyms_on_each_symbol(stat_symbol_len, &total_len);

 	/*
 	 * A symbol name cannot start with a number. This stub name helps us
 	 * traverse the entire symbol table without finding a match. It's used
 	 * for subsequent performance tests, and its length is the average
 	 * length of all symbol names.
 	 */
 	memset(stub_name, '4', sizeof(stub_name));
 	pos = total_len / kallsyms_num_syms;
 	stub_name[pos] = 0;

 	pos = 0;
 	num = 0;
 	off = 0;
 	while (pos < kallsyms_num_syms) {
 		len = kallsyms_names[off];
 		num++;
 		off++;
 		pos++;
 		if ((len & 0x80) != 0) {
 			len = (len & 0x7f) | (kallsyms_names[off] << 7);
 			num++;
 			off++;
 		}
 		off += len;
 	}

 	/*
 	 * 1. The length fields is not counted
 	 * 2. The memory occupied by array kallsyms_token_table[] and
 	 *    kallsyms_token_index[] needs to be counted.
 	 */
 	total_size = off - num;
 	pos = kallsyms_token_index[0xff];
 	total_size += pos + strlen(&kallsyms_token_table[pos]) + 1;
 	total_size += 0x100 * sizeof(u16);

 	pr_info(" ---------------------------------------------------------\n");
 	pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n");
 	pr_info("|---------------------------------------------------------|\n");
 	ratio = (u32)div_u64(10000ULL * total_size, total_len);
 	pr_info("| %10d |    %10d   |   %10d  |  %2d.%-2d   |\n",
 		kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100);
 	pr_info(" ---------------------------------------------------------\n");
 }

 static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr)
 {
 	u64 t0, t1, t;
 	unsigned long flags;
 	struct test_stat *stat = (struct test_stat *)data;

 	local_irq_save(flags);
 	t0 = sched_clock();
 	(void)kallsyms_lookup_name(name);
 	t1 = sched_clock();
 	local_irq_restore(flags);

 	t = t1 - t0;
 	if (t < stat->min)
 		stat->min = t;

 	if (t > stat->max)
 		stat->max = t;

 	stat->real_cnt++;
 	stat->sum += t;

 	return 0;
 }

 static void test_perf_kallsyms_lookup_name(void)
 {
 	struct test_stat stat;

 	memset(&stat, 0, sizeof(stat));
 	stat.min = INT_MAX;
 	kallsyms_on_each_symbol(lookup_name, &stat);
 	pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt);
 	pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n",
 		stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
 }

 static bool match_cleanup_name(const char *s, const char *name)
 {
 	char *p;
 	int len;

 	if (!IS_ENABLED(CONFIG_LTO_CLANG))
 		return false;

 	p = strchr(s, '.');
 	if (!p)
 		return false;

 	len = strlen(name);
 	if (p - s != len)
 		return false;

 	return !strncmp(s, name, len);
 }

 static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr)
 {
 	struct test_stat *stat = (struct test_stat *)data;

 	if (strcmp(name, stat->name) == 0 ||
 	    (!stat->perf && match_cleanup_name(name, stat->name))) {
 		stat->real_cnt++;
 		stat->addr = addr;

 		if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
 			stat->addrs[stat->save_cnt] = addr;
 			stat->save_cnt++;
 		}

 		if (stat->real_cnt == stat->max)
 			return 1;
 	}

 	return 0;
 }

 static void test_perf_kallsyms_on_each_symbol(void)
 {
 	u64 t0, t1;
 	unsigned long flags;
 	struct test_stat stat;

 	memset(&stat, 0, sizeof(stat));
 	stat.max = INT_MAX;
 	stat.name = stub_name;
 	stat.perf = 1;
 	local_irq_save(flags);
 	t0 = sched_clock();
 	kallsyms_on_each_symbol(find_symbol, &stat);
 	t1 = sched_clock();
 	local_irq_restore(flags);
 	pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0);
 }

 static int match_symbol(void *data, unsigned long addr)
 {
 	struct test_stat *stat = (struct test_stat *)data;

 	stat->real_cnt++;
 	stat->addr = addr;

 	if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
 		stat->addrs[stat->save_cnt] = addr;
 		stat->save_cnt++;
 	}

 	if (stat->real_cnt == stat->max)
 		return 1;

 	return 0;
 }

 static void test_perf_kallsyms_on_each_match_symbol(void)
 {
 	u64 t0, t1;
 	unsigned long flags;
 	struct test_stat stat;

 	memset(&stat, 0, sizeof(stat));
 	stat.max = INT_MAX;
 	stat.name = stub_name;
 	local_irq_save(flags);
 	t0 = sched_clock();
 	kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat);
 	t1 = sched_clock();
 	local_irq_restore(flags);
 	pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0);
 }

 static int test_kallsyms_basic_function(void)
 {
 	int i, j, ret;
 	int next = 0, nr_failed = 0;
 	char *prefix;
 	unsigned short rand;
 	unsigned long addr, lookup_addr;
 	char namebuf[KSYM_NAME_LEN];
 	struct test_stat *stat, *stat2;

 	stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL);
 	if (!stat)
 		return -ENOMEM;
 	stat2 = stat + 1;

 	prefix = "kallsyms_lookup_name() for";
 	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
 		addr = kallsyms_lookup_name(test_items[i].name);
 		if (addr != test_items[i].addr) {
 			nr_failed++;
 			pr_info("%s %s failed: addr=%lx, expect %lx\n",
 				prefix, test_items[i].name, addr, test_items[i].addr);
 		}
 	}

 	prefix = "kallsyms_on_each_symbol() for";
 	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
 		memset(stat, 0, sizeof(*stat));
 		stat->max = INT_MAX;
 		stat->name = test_items[i].name;
 		kallsyms_on_each_symbol(find_symbol, stat);
 		if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
 			nr_failed++;
 			pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
 				prefix, test_items[i].name,
 				stat->real_cnt, stat->addr, test_items[i].addr);
 		}
 	}

 	prefix = "kallsyms_on_each_match_symbol() for";
 	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
 		memset(stat, 0, sizeof(*stat));
 		stat->max = INT_MAX;
 		stat->name = test_items[i].name;
 		kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat);
 		if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
 			nr_failed++;
 			pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
 				prefix, test_items[i].name,
 				stat->real_cnt, stat->addr, test_items[i].addr);
 		}
 	}

 	if (nr_failed) {
 		kfree(stat);
 		return -ESRCH;
 	}

 	for (i = 0; i < kallsyms_num_syms; i++) {
 		addr = kallsyms_sym_address(i);
 		if (!is_ksym_addr(addr))
 			continue;

 		ret = lookup_symbol_name(addr, namebuf);
 		if (unlikely(ret)) {
 			namebuf[0] = 0;
 			goto failed;
 		}

 		/*
 		 * The first '.' may be the initial letter, in which case the
 		 * entire symbol name will be truncated to an empty string in
 		 * cleanup_symbol_name(). Do not test these symbols.
 		 *
 		 * For example:
 		 * cat /proc/kallsyms | awk '{print $3}' | grep -E "^\." | head
 		 * .E_read_words
 		 * .E_leading_bytes
 		 * .E_trailing_bytes
 		 * .E_write_words
 		 * .E_copy
 		 * .str.292.llvm.12122243386960820698
 		 * .str.24.llvm.12122243386960820698
 		 * .str.29.llvm.12122243386960820698
 		 * .str.75.llvm.12122243386960820698
 		 * .str.99.llvm.12122243386960820698
 		 */
 		if (IS_ENABLED(CONFIG_LTO_CLANG) && !namebuf[0])
 			continue;

 		lookup_addr = kallsyms_lookup_name(namebuf);

 		memset(stat, 0, sizeof(*stat));
 		stat->max = INT_MAX;
 		kallsyms_on_each_match_symbol(match_symbol, namebuf, stat);

 		/*
 		 * kallsyms_on_each_symbol() is too slow, randomly select some
 		 * symbols for test.
 		 */
 		if (i >= next) {
 			memset(stat2, 0, sizeof(*stat2));
 			stat2->max = INT_MAX;
 			stat2->name = namebuf;
 			kallsyms_on_each_symbol(find_symbol, stat2);

 			/*
 			 * kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()
 			 * need to get the same traversal result.
 			 */
 			if (stat->addr != stat2->addr ||
 			    stat->real_cnt != stat2->real_cnt ||
 			    memcmp(stat->addrs, stat2->addrs,
 				   stat->save_cnt * sizeof(stat->addrs[0])))
 				goto failed;

 			/*
 			 * The average of random increments is 128, that is, one of
 			 * them is tested every 128 symbols.
 			 */
 			get_random_bytes(&rand, sizeof(rand));
 			next = i + (rand & 0xff) + 1;
 		}

 		/* Need to be found at least once */
 		if (!stat->real_cnt)
 			goto failed;

 		/*
 		 * kallsyms_lookup_name() returns the address of the first
 		 * symbol found and cannot be NULL.
 		 */
 		if (!lookup_addr || lookup_addr != stat->addrs[0])
 			goto failed;

 		/*
 		 * If the addresses of all matching symbols are recorded, the
 		 * target address needs to be exist.
 		 */
 		if (stat->real_cnt <= MAX_NUM_OF_RECORDS) {
 			for (j = 0; j < stat->save_cnt; j++) {
 				if (stat->addrs[j] == addr)
 					break;
 			}

 			if (j == stat->save_cnt)
 				goto failed;
 		}
 	}

 	kfree(stat);

 	return 0;

 failed:
 	pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr);
 	kfree(stat);
 	return -ESRCH;
 }

 static int test_entry(void *p)
 {
 	int ret;

 	do {
 		schedule_timeout(5 * HZ);
 	} while (system_state != SYSTEM_RUNNING);

 	pr_info("start\n");
 	ret = test_kallsyms_basic_function();
 	if (ret) {
 		pr_info("abort\n");
 		return 0;
 	}

 	test_kallsyms_compression_ratio();
 	test_perf_kallsyms_lookup_name();
 	test_perf_kallsyms_on_each_symbol();
 	test_perf_kallsyms_on_each_match_symbol();
 	pr_info("finish\n");

 	return 0;
 }

 static int __init kallsyms_test_init(void)
 {
 	struct task_struct *t;

 	t = kthread_create(test_entry, NULL, "kallsyms_test");
 	if (IS_ERR(t)) {
 		pr_info("Create kallsyms selftest task failed\n");
 		return PTR_ERR(t);
 	}
 	kthread_bind(t, 0);
 	wake_up_process(t);

 	return 0;
 }
 late_initcall(kallsyms_test_init);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Test the function and performance of kallsyms
	*
	* Copyright (C) Huawei Technologies Co., Ltd., 2022
	*
	* Authors: Zhen Lei <thunder.leizhen@huawei.com> Huawei
	*/

	#define pr_fmt(fmt) "kallsyms_selftest: " fmt

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kallsyms.h>
	#include <linux/random.h>
	#include <linux/sched/clock.h>
	#include <linux/kthread.h>
	#include <linux/vmalloc.h>

	#include "kallsyms_internal.h"
	#include "kallsyms_selftest.h"


	#define MAX_NUM_OF_RECORDS 64

	struct test_stat {
	int min;
	int max;
	int save_cnt;
	int real_cnt;
	int perf;
	u64 sum;
	char *name;
	unsigned long addr;
	unsigned long addrs[MAX_NUM_OF_RECORDS];
	};

	struct test_item {
	char *name;
	unsigned long addr;
	};

	#define ITEM_FUNC(s) \
	{ \
	.name = #s, \
	.addr = (unsigned long)s, \
	}

	#define ITEM_DATA(s) \
	{ \
	.name = #s, \
	.addr = (unsigned long)&s, \
	}


	static int kallsyms_test_var_bss_static;
	static int kallsyms_test_var_data_static = 1;
	int kallsyms_test_var_bss;
	int kallsyms_test_var_data = 1;

	static int kallsyms_test_func_static(void)
	{
	kallsyms_test_var_bss_static++;
	kallsyms_test_var_data_static++;

	return 0;
	}

	int kallsyms_test_func(void)
	{
	return kallsyms_test_func_static();
	}

	__weak int kallsyms_test_func_weak(void)
	{
	kallsyms_test_var_bss++;
	kallsyms_test_var_data++;
	return 0;
	}

	static struct test_item test_items[] = {
	ITEM_FUNC(kallsyms_test_func_static),
	ITEM_FUNC(kallsyms_test_func),
	ITEM_FUNC(kallsyms_test_func_weak),
	ITEM_FUNC(vmalloc),
	ITEM_FUNC(vfree),
	#ifdef CONFIG_KALLSYMS_ALL
	ITEM_DATA(kallsyms_test_var_bss_static),
	ITEM_DATA(kallsyms_test_var_data_static),
	ITEM_DATA(kallsyms_test_var_bss),
	ITEM_DATA(kallsyms_test_var_data),
	ITEM_DATA(vmap_area_list),
	#endif
	};

	static char stub_name[KSYM_NAME_LEN];

	static int stat_symbol_len(void data, const char name, struct module *mod, unsigned long addr)
	{
	(u32 )data += strlen(name);

	return 0;
	}

	static void test_kallsyms_compression_ratio(void)
	{
	u32 pos, off, len, num;
	u32 ratio, total_size, total_len = 0;

	kallsyms_on_each_symbol(stat_symbol_len, &total_len);

	/*
	* A symbol name cannot start with a number. This stub name helps us
	* traverse the entire symbol table without finding a match. It's used
	* for subsequent performance tests, and its length is the average
	* length of all symbol names.
	*/
	memset(stub_name, '4', sizeof(stub_name));
	pos = total_len / kallsyms_num_syms;
	stub_name[pos] = 0;

	pos = 0;
	num = 0;
	off = 0;
	while (pos < kallsyms_num_syms) {
	len = kallsyms_names[off];
	num++;
	off++;
	pos++;
	if ((len & 0x80) != 0) {
	len = (len & 0x7f) \| (kallsyms_names[off] << 7);
	num++;
	off++;
	}
	off += len;
	}

	/*
	* 1. The length fields is not counted
	* 2. The memory occupied by array kallsyms_token_table[] and
	* kallsyms_token_index[] needs to be counted.
	*/
	total_size = off - num;
	pos = kallsyms_token_index[0xff];
	total_size += pos + strlen(&kallsyms_token_table[pos]) + 1;
	total_size += 0x100 * sizeof(u16);

	pr_info(" ---------------------------------------------------------\n");
	pr_info("\| nr_symbols \| compressed size \| original size \| ratio(%%) \|\n");
	pr_info("\|---------------------------------------------------------\|\n");
	ratio = (u32)div_u64(10000ULL * total_size, total_len);
	pr_info("\| %10d \| %10d \| %10d \| %2d.%-2d \|\n",
	kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100);
	pr_info(" ---------------------------------------------------------\n");
	}

	static int lookup_name(void data, const char name, struct module *mod, unsigned long addr)
	{
	u64 t0, t1, t;
	unsigned long flags;
	struct test_stat stat = (struct test_stat )data;

	local_irq_save(flags);
	t0 = sched_clock();
	(void)kallsyms_lookup_name(name);
	t1 = sched_clock();
	local_irq_restore(flags);

	t = t1 - t0;
	if (t < stat->min)
	stat->min = t;

	if (t > stat->max)
	stat->max = t;

	stat->real_cnt++;
	stat->sum += t;

	return 0;
	}

	static void test_perf_kallsyms_lookup_name(void)
	{
	struct test_stat stat;

	memset(&stat, 0, sizeof(stat));
	stat.min = INT_MAX;
	kallsyms_on_each_symbol(lookup_name, &stat);
	pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt);
	pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n",
	stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
	}

	static bool match_cleanup_name(const char s, const char name)
	{
	char *p;
	int len;

	if (!IS_ENABLED(CONFIG_LTO_CLANG))
	return false;

	p = strchr(s, '.');
	if (!p)
	return false;

	len = strlen(name);
	if (p - s != len)
	return false;

	return !strncmp(s, name, len);
	}

	static int find_symbol(void data, const char name, struct module *mod, unsigned long addr)
	{
	struct test_stat stat = (struct test_stat )data;

	if (strcmp(name, stat->name) == 0 \|\|
	(!stat->perf && match_cleanup_name(name, stat->name))) {
	stat->real_cnt++;
	stat->addr = addr;

	if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
	stat->addrs[stat->save_cnt] = addr;
	stat->save_cnt++;
	}

	if (stat->real_cnt == stat->max)
	return 1;
	}

	return 0;
	}

	static void test_perf_kallsyms_on_each_symbol(void)
	{
	u64 t0, t1;
	unsigned long flags;
	struct test_stat stat;

	memset(&stat, 0, sizeof(stat));
	stat.max = INT_MAX;
	stat.name = stub_name;
	stat.perf = 1;
	local_irq_save(flags);
	t0 = sched_clock();
	kallsyms_on_each_symbol(find_symbol, &stat);
	t1 = sched_clock();
	local_irq_restore(flags);
	pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0);
	}

	static int match_symbol(void *data, unsigned long addr)
	{
	struct test_stat stat = (struct test_stat )data;

	stat->real_cnt++;
	stat->addr = addr;

	if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
	stat->addrs[stat->save_cnt] = addr;
	stat->save_cnt++;
	}

	if (stat->real_cnt == stat->max)
	return 1;

	return 0;
	}

	static void test_perf_kallsyms_on_each_match_symbol(void)
	{
	u64 t0, t1;
	unsigned long flags;
	struct test_stat stat;

	memset(&stat, 0, sizeof(stat));
	stat.max = INT_MAX;
	stat.name = stub_name;
	local_irq_save(flags);
	t0 = sched_clock();
	kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat);
	t1 = sched_clock();
	local_irq_restore(flags);
	pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0);
	}

	static int test_kallsyms_basic_function(void)
	{
	int i, j, ret;
	int next = 0, nr_failed = 0;
	char *prefix;
	unsigned short rand;
	unsigned long addr, lookup_addr;
	char namebuf[KSYM_NAME_LEN];
	struct test_stat stat, stat2;

	stat = kmalloc(sizeof(stat) 2, GFP_KERNEL);
	if (!stat)
	return -ENOMEM;
	stat2 = stat + 1;

	prefix = "kallsyms_lookup_name() for";
	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
	addr = kallsyms_lookup_name(test_items[i].name);
	if (addr != test_items[i].addr) {
	nr_failed++;
	pr_info("%s %s failed: addr=%lx, expect %lx\n",
	prefix, test_items[i].name, addr, test_items[i].addr);
	}
	}

	prefix = "kallsyms_on_each_symbol() for";
	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
	memset(stat, 0, sizeof(*stat));
	stat->max = INT_MAX;
	stat->name = test_items[i].name;
	kallsyms_on_each_symbol(find_symbol, stat);
	if (stat->addr != test_items[i].addr \|\| stat->real_cnt != 1) {
	nr_failed++;
	pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
	prefix, test_items[i].name,
	stat->real_cnt, stat->addr, test_items[i].addr);
	}
	}

	prefix = "kallsyms_on_each_match_symbol() for";
	for (i = 0; i < ARRAY_SIZE(test_items); i++) {
	memset(stat, 0, sizeof(*stat));
	stat->max = INT_MAX;
	stat->name = test_items[i].name;
	kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat);
	if (stat->addr != test_items[i].addr \|\| stat->real_cnt != 1) {
	nr_failed++;
	pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
	prefix, test_items[i].name,
	stat->real_cnt, stat->addr, test_items[i].addr);
	}
	}

	if (nr_failed) {
	kfree(stat);
	return -ESRCH;
	}

	for (i = 0; i < kallsyms_num_syms; i++) {
	addr = kallsyms_sym_address(i);
	if (!is_ksym_addr(addr))
	continue;

	ret = lookup_symbol_name(addr, namebuf);
	if (unlikely(ret)) {
	namebuf[0] = 0;
	goto failed;
	}

	/*
	* The first '.' may be the initial letter, in which case the
	* entire symbol name will be truncated to an empty string in
	* cleanup_symbol_name(). Do not test these symbols.
	*
	* For example:
	* cat /proc/kallsyms \| awk '{print $3}' \| grep -E "^\." \| head
	* .E_read_words
	* .E_leading_bytes
	* .E_trailing_bytes
	* .E_write_words
	* .E_copy
	* .str.292.llvm.12122243386960820698
	* .str.24.llvm.12122243386960820698
	* .str.29.llvm.12122243386960820698
	* .str.75.llvm.12122243386960820698
	* .str.99.llvm.12122243386960820698
	*/
	if (IS_ENABLED(CONFIG_LTO_CLANG) && !namebuf[0])
	continue;

	lookup_addr = kallsyms_lookup_name(namebuf);

	memset(stat, 0, sizeof(*stat));
	stat->max = INT_MAX;
	kallsyms_on_each_match_symbol(match_symbol, namebuf, stat);

	/*
	* kallsyms_on_each_symbol() is too slow, randomly select some
	* symbols for test.
	*/
	if (i >= next) {
	memset(stat2, 0, sizeof(*stat2));
	stat2->max = INT_MAX;
	stat2->name = namebuf;
	kallsyms_on_each_symbol(find_symbol, stat2);

	/*
	* kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()
	* need to get the same traversal result.
	*/
	if (stat->addr != stat2->addr \|\|
	stat->real_cnt != stat2->real_cnt \|\|
	memcmp(stat->addrs, stat2->addrs,
	stat->save_cnt * sizeof(stat->addrs[0])))
	goto failed;

	/*
	* The average of random increments is 128, that is, one of
	* them is tested every 128 symbols.
	*/
	get_random_bytes(&rand, sizeof(rand));
	next = i + (rand & 0xff) + 1;
	}

	/* Need to be found at least once */
	if (!stat->real_cnt)
	goto failed;

	/*
	* kallsyms_lookup_name() returns the address of the first
	* symbol found and cannot be NULL.
	*/
	if (!lookup_addr \|\| lookup_addr != stat->addrs[0])
	goto failed;

	/*
	* If the addresses of all matching symbols are recorded, the
	* target address needs to be exist.
	*/
	if (stat->real_cnt <= MAX_NUM_OF_RECORDS) {
	for (j = 0; j < stat->save_cnt; j++) {
	if (stat->addrs[j] == addr)
	break;
	}

	if (j == stat->save_cnt)
	goto failed;
	}
	}

	kfree(stat);

	return 0;

	failed:
	pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr);
	kfree(stat);
	return -ESRCH;
	}

	static int test_entry(void *p)
	{
	int ret;

	do {
	schedule_timeout(5 * HZ);
	} while (system_state != SYSTEM_RUNNING);

	pr_info("start\n");
	ret = test_kallsyms_basic_function();
	if (ret) {
	pr_info("abort\n");
	return 0;
	}

	test_kallsyms_compression_ratio();
	test_perf_kallsyms_lookup_name();
	test_perf_kallsyms_on_each_symbol();
	test_perf_kallsyms_on_each_match_symbol();
	pr_info("finish\n");

	return 0;
	}

	static int __init kallsyms_test_init(void)
	{
	struct task_struct *t;

	t = kthread_create(test_entry, NULL, "kallsyms_test");
	if (IS_ERR(t)) {
	pr_info("Create kallsyms selftest task failed\n");
	return PTR_ERR(t);
	}
	kthread_bind(t, 0);
	wake_up_process(t);

	return 0;
	}
	late_initcall(kallsyms_test_init);