cat /proc/kallsyms found that the kernel symbol table values ​​are all 0

Recently debugging the kernel, after cat /proc/kallsyms found that the symbol table values ​​are all 0.

Check the kernel configuration items, the configuration has been configured.

Finding a lot of online information, it is said that the kernel deliberately prevents non-root users from viewing the symbol table in order to prevent the occurrence of vulnerabilities.

But if I switch the shell to root, I can only see 0.

Therefore, only the kernel code can be modified.kernel/kernel/kallsyms.c

static int s_show(struct seq_file *m, void *p)
{
struct kallsym_iter *iter = m->private;

 /* Some debugging symbols have no name. Ignore them. */if (!iter->name[0])return 0;if (iter->module_name[0]) {char type;/** Label it "global" if it is exported,* "local" if not exported.*/type = iter->exported ? toupper(iter->type) :tolower(iter->type);seq_printf(m, "%pK %c %s\t[%s]\n", (void *)iter->value,type, iter->name, iter->module_name);} elseseq_printf(m, "%pK %c %s\n", (void *)iter->value,iter->type, iter->name);return 0;

}
Need to seq_printf(m, “%pK %c %s\t[%s]\n”, (void *)iter->value,
type, iter->name, iter->module_name); Remove the K in it and recompile and program the kernel.

seq_printf(m, “%p %c %s\t[%s]\n”, (void *)iter->value,
type, iter->name, iter->module_name);