::
%pK 01234567 or 0123456789abcdef
For printing kernel pointers which should be hidden from unprivileged users. The behaviour of %pK depends on the kptr_restrict sysctl - see Documentation/admin-guide/sysctl/kernel.rst for more details.
This modifier is only intended when producing content of a file read by userspace from e.g. procfs or sysfs, not for dmesg. Please refer to the section about %p above for discussion about how to manage hashing pointers in printk().