os_info_csum
u32 os_info_csum(struct os_info *os_info);
if (os_info_old->csum != os_info_csum(os_info_old))
os_info.csum = os_info_csum(&os_info);
os_info.csum = os_info_csum(&os_info);
os_info.csum = os_info_csum(&os_info);
os_info.csum = os_info_csum(&os_info);
if (rc || os_info_csum(os_info) != os_info->csum)