Error code -19 means NODEV, please check if the running kernel enables the
kernel config option CONFIG_ZONE_DEVICE (read kernel config from file
/proc/config.gz).

init_user_pages return -NODEV if userptr support is not enabled, userptr
support depends on kernel option CONFIG_HMM_MIRROR/CONFIG_HMM, which depends on
kernel option CONFIG_ZONE_DEVICE.

CONFIG_ZONE_DEVICE, CONFIG_HMM is by default ON, but kernel config file may not
select to set CONFIG_ZONE_DEVICE if the kernel config file is from old kernel.

If userptr support is not enabled, then clinfo and KFD usreptr support will
return error -19.

Please correct kernel config file by adding CONFIG_ZONE_DEVICE=y