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![Nicholas Piggin](/assets/img/avatar_default.png)
kallsyms_on_each* may schedule so must not be called with interrupts
disabled. The iteration function could disable interrupts, but this
also changes lookup_symbol() to match the change to the other timing
code.
Reported-by: Erhard F. <erhard_f@mailbox.org>
Link: https://lore.kernel.org/all/bug-216902-206035@https.bugzilla.kernel.org%2F/
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202212251728.8d0872ff-oliver.sang@intel.com
Fixes: 30f3bb0977
("kallsyms: Add self-test facility")
Tested-by: "Erhard F." <erhard_f@mailbox.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
476 lines
11 KiB
C
476 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Test the function and performance of kallsyms
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*
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* Copyright (C) Huawei Technologies Co., Ltd., 2022
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*
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* Authors: Zhen Lei <thunder.leizhen@huawei.com> Huawei
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*/
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#define pr_fmt(fmt) "kallsyms_selftest: " fmt
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kallsyms.h>
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#include <linux/random.h>
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#include <linux/sched/clock.h>
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#include <linux/kthread.h>
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#include <linux/vmalloc.h>
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#include "kallsyms_internal.h"
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#include "kallsyms_selftest.h"
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#define MAX_NUM_OF_RECORDS 64
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struct test_stat {
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int min;
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int max;
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int save_cnt;
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int real_cnt;
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int perf;
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u64 sum;
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char *name;
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unsigned long addr;
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unsigned long addrs[MAX_NUM_OF_RECORDS];
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};
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struct test_item {
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char *name;
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unsigned long addr;
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};
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#define ITEM_FUNC(s) \
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{ \
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.name = #s, \
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.addr = (unsigned long)s, \
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}
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#define ITEM_DATA(s) \
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{ \
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.name = #s, \
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.addr = (unsigned long)&s, \
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}
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static int kallsyms_test_var_bss_static;
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static int kallsyms_test_var_data_static = 1;
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int kallsyms_test_var_bss;
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int kallsyms_test_var_data = 1;
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static int kallsyms_test_func_static(void)
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{
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kallsyms_test_var_bss_static++;
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kallsyms_test_var_data_static++;
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return 0;
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}
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int kallsyms_test_func(void)
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{
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return kallsyms_test_func_static();
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}
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__weak int kallsyms_test_func_weak(void)
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{
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kallsyms_test_var_bss++;
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kallsyms_test_var_data++;
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return 0;
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}
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static struct test_item test_items[] = {
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ITEM_FUNC(kallsyms_test_func_static),
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ITEM_FUNC(kallsyms_test_func),
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ITEM_FUNC(kallsyms_test_func_weak),
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ITEM_FUNC(vmalloc),
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ITEM_FUNC(vfree),
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#ifdef CONFIG_KALLSYMS_ALL
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ITEM_DATA(kallsyms_test_var_bss_static),
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ITEM_DATA(kallsyms_test_var_data_static),
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ITEM_DATA(kallsyms_test_var_bss),
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ITEM_DATA(kallsyms_test_var_data),
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ITEM_DATA(vmap_area_list),
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#endif
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};
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static char stub_name[KSYM_NAME_LEN];
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static int stat_symbol_len(void *data, const char *name, struct module *mod, unsigned long addr)
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{
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*(u32 *)data += strlen(name);
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return 0;
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}
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static void test_kallsyms_compression_ratio(void)
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{
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u32 pos, off, len, num;
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u32 ratio, total_size, total_len = 0;
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kallsyms_on_each_symbol(stat_symbol_len, &total_len);
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/*
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* A symbol name cannot start with a number. This stub name helps us
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* traverse the entire symbol table without finding a match. It's used
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* for subsequent performance tests, and its length is the average
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* length of all symbol names.
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*/
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memset(stub_name, '4', sizeof(stub_name));
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pos = total_len / kallsyms_num_syms;
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stub_name[pos] = 0;
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pos = 0;
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num = 0;
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off = 0;
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while (pos < kallsyms_num_syms) {
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len = kallsyms_names[off];
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num++;
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off++;
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pos++;
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if ((len & 0x80) != 0) {
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len = (len & 0x7f) | (kallsyms_names[off] << 7);
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num++;
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off++;
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}
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off += len;
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}
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/*
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* 1. The length fields is not counted
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* 2. The memory occupied by array kallsyms_token_table[] and
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* kallsyms_token_index[] needs to be counted.
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*/
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total_size = off - num;
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pos = kallsyms_token_index[0xff];
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total_size += pos + strlen(&kallsyms_token_table[pos]) + 1;
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total_size += 0x100 * sizeof(u16);
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pr_info(" ---------------------------------------------------------\n");
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pr_info("| nr_symbols | compressed size | original size | ratio(%%) |\n");
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pr_info("|---------------------------------------------------------|\n");
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ratio = (u32)div_u64(10000ULL * total_size, total_len);
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pr_info("| %10d | %10d | %10d | %2d.%-2d |\n",
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kallsyms_num_syms, total_size, total_len, ratio / 100, ratio % 100);
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pr_info(" ---------------------------------------------------------\n");
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}
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static int lookup_name(void *data, const char *name, struct module *mod, unsigned long addr)
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{
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u64 t0, t1, t;
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struct test_stat *stat = (struct test_stat *)data;
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t0 = ktime_get_ns();
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(void)kallsyms_lookup_name(name);
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t1 = ktime_get_ns();
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t = t1 - t0;
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if (t < stat->min)
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stat->min = t;
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if (t > stat->max)
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stat->max = t;
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stat->real_cnt++;
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stat->sum += t;
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return 0;
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}
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static void test_perf_kallsyms_lookup_name(void)
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{
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struct test_stat stat;
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memset(&stat, 0, sizeof(stat));
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stat.min = INT_MAX;
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kallsyms_on_each_symbol(lookup_name, &stat);
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pr_info("kallsyms_lookup_name() looked up %d symbols\n", stat.real_cnt);
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pr_info("The time spent on each symbol is (ns): min=%d, max=%d, avg=%lld\n",
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stat.min, stat.max, div_u64(stat.sum, stat.real_cnt));
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}
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static bool match_cleanup_name(const char *s, const char *name)
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{
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char *p;
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int len;
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if (!IS_ENABLED(CONFIG_LTO_CLANG))
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return false;
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p = strchr(s, '.');
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if (!p)
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return false;
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len = strlen(name);
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if (p - s != len)
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return false;
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return !strncmp(s, name, len);
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}
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static int find_symbol(void *data, const char *name, struct module *mod, unsigned long addr)
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{
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struct test_stat *stat = (struct test_stat *)data;
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if (strcmp(name, stat->name) == 0 ||
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(!stat->perf && match_cleanup_name(name, stat->name))) {
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stat->real_cnt++;
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stat->addr = addr;
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if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
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stat->addrs[stat->save_cnt] = addr;
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stat->save_cnt++;
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}
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if (stat->real_cnt == stat->max)
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return 1;
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}
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return 0;
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}
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static void test_perf_kallsyms_on_each_symbol(void)
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{
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u64 t0, t1;
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struct test_stat stat;
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memset(&stat, 0, sizeof(stat));
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stat.max = INT_MAX;
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stat.name = stub_name;
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stat.perf = 1;
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t0 = ktime_get_ns();
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kallsyms_on_each_symbol(find_symbol, &stat);
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t1 = ktime_get_ns();
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pr_info("kallsyms_on_each_symbol() traverse all: %lld ns\n", t1 - t0);
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}
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static int match_symbol(void *data, unsigned long addr)
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{
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struct test_stat *stat = (struct test_stat *)data;
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stat->real_cnt++;
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stat->addr = addr;
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if (stat->save_cnt < MAX_NUM_OF_RECORDS) {
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stat->addrs[stat->save_cnt] = addr;
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stat->save_cnt++;
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}
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if (stat->real_cnt == stat->max)
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return 1;
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return 0;
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}
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static void test_perf_kallsyms_on_each_match_symbol(void)
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{
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u64 t0, t1;
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struct test_stat stat;
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memset(&stat, 0, sizeof(stat));
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stat.max = INT_MAX;
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stat.name = stub_name;
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t0 = ktime_get_ns();
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kallsyms_on_each_match_symbol(match_symbol, stat.name, &stat);
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t1 = ktime_get_ns();
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pr_info("kallsyms_on_each_match_symbol() traverse all: %lld ns\n", t1 - t0);
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}
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static int test_kallsyms_basic_function(void)
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{
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int i, j, ret;
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int next = 0, nr_failed = 0;
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char *prefix;
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unsigned short rand;
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unsigned long addr, lookup_addr;
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char namebuf[KSYM_NAME_LEN];
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struct test_stat *stat, *stat2;
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stat = kmalloc(sizeof(*stat) * 2, GFP_KERNEL);
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if (!stat)
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return -ENOMEM;
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stat2 = stat + 1;
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prefix = "kallsyms_lookup_name() for";
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for (i = 0; i < ARRAY_SIZE(test_items); i++) {
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addr = kallsyms_lookup_name(test_items[i].name);
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if (addr != test_items[i].addr) {
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nr_failed++;
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pr_info("%s %s failed: addr=%lx, expect %lx\n",
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prefix, test_items[i].name, addr, test_items[i].addr);
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}
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}
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prefix = "kallsyms_on_each_symbol() for";
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for (i = 0; i < ARRAY_SIZE(test_items); i++) {
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memset(stat, 0, sizeof(*stat));
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stat->max = INT_MAX;
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stat->name = test_items[i].name;
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kallsyms_on_each_symbol(find_symbol, stat);
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if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
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nr_failed++;
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pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
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prefix, test_items[i].name,
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stat->real_cnt, stat->addr, test_items[i].addr);
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}
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}
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prefix = "kallsyms_on_each_match_symbol() for";
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for (i = 0; i < ARRAY_SIZE(test_items); i++) {
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memset(stat, 0, sizeof(*stat));
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stat->max = INT_MAX;
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stat->name = test_items[i].name;
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kallsyms_on_each_match_symbol(match_symbol, test_items[i].name, stat);
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if (stat->addr != test_items[i].addr || stat->real_cnt != 1) {
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nr_failed++;
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pr_info("%s %s failed: count=%d, addr=%lx, expect %lx\n",
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prefix, test_items[i].name,
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stat->real_cnt, stat->addr, test_items[i].addr);
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}
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}
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if (nr_failed) {
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kfree(stat);
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return -ESRCH;
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}
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for (i = 0; i < kallsyms_num_syms; i++) {
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addr = kallsyms_sym_address(i);
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if (!is_ksym_addr(addr))
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continue;
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ret = lookup_symbol_name(addr, namebuf);
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if (unlikely(ret)) {
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namebuf[0] = 0;
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goto failed;
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}
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/*
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* The first '.' may be the initial letter, in which case the
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* entire symbol name will be truncated to an empty string in
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* cleanup_symbol_name(). Do not test these symbols.
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*
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* For example:
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* cat /proc/kallsyms | awk '{print $3}' | grep -E "^\." | head
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* .E_read_words
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* .E_leading_bytes
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* .E_trailing_bytes
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* .E_write_words
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* .E_copy
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* .str.292.llvm.12122243386960820698
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* .str.24.llvm.12122243386960820698
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* .str.29.llvm.12122243386960820698
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* .str.75.llvm.12122243386960820698
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* .str.99.llvm.12122243386960820698
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*/
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if (IS_ENABLED(CONFIG_LTO_CLANG) && !namebuf[0])
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continue;
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lookup_addr = kallsyms_lookup_name(namebuf);
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memset(stat, 0, sizeof(*stat));
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stat->max = INT_MAX;
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kallsyms_on_each_match_symbol(match_symbol, namebuf, stat);
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/*
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* kallsyms_on_each_symbol() is too slow, randomly select some
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* symbols for test.
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*/
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if (i >= next) {
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memset(stat2, 0, sizeof(*stat2));
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stat2->max = INT_MAX;
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stat2->name = namebuf;
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kallsyms_on_each_symbol(find_symbol, stat2);
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/*
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* kallsyms_on_each_symbol() and kallsyms_on_each_match_symbol()
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* need to get the same traversal result.
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*/
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if (stat->addr != stat2->addr ||
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stat->real_cnt != stat2->real_cnt ||
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memcmp(stat->addrs, stat2->addrs,
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stat->save_cnt * sizeof(stat->addrs[0])))
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goto failed;
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/*
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* The average of random increments is 128, that is, one of
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* them is tested every 128 symbols.
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*/
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get_random_bytes(&rand, sizeof(rand));
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next = i + (rand & 0xff) + 1;
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}
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/* Need to be found at least once */
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if (!stat->real_cnt)
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goto failed;
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/*
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* kallsyms_lookup_name() returns the address of the first
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* symbol found and cannot be NULL.
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*/
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if (!lookup_addr || lookup_addr != stat->addrs[0])
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goto failed;
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/*
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* If the addresses of all matching symbols are recorded, the
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* target address needs to be exist.
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*/
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if (stat->real_cnt <= MAX_NUM_OF_RECORDS) {
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for (j = 0; j < stat->save_cnt; j++) {
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if (stat->addrs[j] == addr)
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break;
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}
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if (j == stat->save_cnt)
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goto failed;
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}
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}
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kfree(stat);
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return 0;
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failed:
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pr_info("Test for %dth symbol failed: (%s) addr=%lx", i, namebuf, addr);
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kfree(stat);
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return -ESRCH;
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}
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static int test_entry(void *p)
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{
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int ret;
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do {
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schedule_timeout(5 * HZ);
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} while (system_state != SYSTEM_RUNNING);
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pr_info("start\n");
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ret = test_kallsyms_basic_function();
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if (ret) {
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pr_info("abort\n");
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return 0;
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}
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test_kallsyms_compression_ratio();
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test_perf_kallsyms_lookup_name();
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test_perf_kallsyms_on_each_symbol();
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test_perf_kallsyms_on_each_match_symbol();
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pr_info("finish\n");
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return 0;
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}
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static int __init kallsyms_test_init(void)
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{
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struct task_struct *t;
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t = kthread_create(test_entry, NULL, "kallsyms_test");
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if (IS_ERR(t)) {
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pr_info("Create kallsyms selftest task failed\n");
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return PTR_ERR(t);
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}
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kthread_bind(t, 0);
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wake_up_process(t);
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return 0;
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}
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late_initcall(kallsyms_test_init);
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