checked_open
fd = checked_open(name, O_RDONLY|O_NOATIME|O_NOFOLLOW);
kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
pagemap_fd = checked_open("/proc/self/pagemap", O_RDONLY);
kpagecgroup_fd = checked_open(PROC_KPAGECGROUP, O_RDONLY);
kpagecount_fd = checked_open(PROC_KPAGECOUNT, O_RDONLY);
page_idle_fd = checked_open(SYS_KERNEL_MM_PAGE_IDLE, O_RDWR);
hwpoison_inject_fd = checked_open(buf, O_WRONLY);
hwpoison_forget_fd = checked_open(buf, O_WRONLY);
kpageflags_fd = checked_open(opt_kpageflags, O_RDONLY);
pagemap_fd = checked_open(buf, O_RDONLY);