cat /proc/kallsyms 发现内核符号表值都为0

最近调试内核，cat /proc/kallsyms 后发现符号表值都为0。

检查内核配置项，该配的都已经配置。

查找很多网上资料，说是内核为了防止漏洞出现，特意不让非root用户查看符号表。

但是我将shell切换为root，还是只能查看到0.

因此只能修改内核代码。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);
    } else
            seq_printf(m, "%pK %c %s\n", (void *)iter->value,
                       iter->type, iter->name);
    return 0;

}
需要将seq_printf(m, “%pK %c %s\t[%s]\n”, (void *)iter->value,
type, iter->name, iter->module_name); 中的K去掉，重新编译烧写内核即可。

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