Do not use this feature without some mechanism to verify the
correctness of the format string and va_list arguments.
-u64 SHOULD be printed with %llu/%llx, (unsigned long long):
+u64 SHOULD be printed with %llu/%llx:
printk("%llu", u64_var);
-s64 SHOULD be printed with %lld/%llx, (long long):
+s64 SHOULD be printed with %lld/%llx:
printk("%lld", s64_var);