dmesg shows NFIT related messages after updating the kernel

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Environment

SUSE Linux Enterprise Server 15 SP2
SUSE Linux Enterprise Server 15 SP1

Situation

When a system with NVDIMM-N/AEP is booted into SUSE Linux Enterprise Server 15 SP1, dmesg displays unknown symbol messages.
The following are examples of NVDIMM firmware interface table (NFIT) error messages that are displayed in dmesg:

Unknown symbol nvdimm_blk_region_create (err 0)
Unknown symbol nvdimm_region_notify (err 0)
Unknown symbol to_nvdimm_bus (err 0)

Resolution

These messages will no longer be seen in SUSE Linux Enterprise 15 SP2.
The "90nvdimm" module for dracut helps resolve the dependencies.

To work around the issue in SUSE Linux Enterprise Server 15 SP1, create /etc/modprobe.d/95-nvdimm.conf with the following content:

# SUSE INITRD: nfit REQUIRES libnvdimm
# SUSE INITRD: nd_btt REQUIRES libnvdimm
# SUSE INITRD: dax_pmem REQUIRES libnvdimm

Cause

When installing the maintenance update kernel, the Dracut missed including the libnvdimm kernel module in initramfs which is a dependency for the nfit driver to load.
Since the libnvdimm driver is missing, nfit driver load fails with ‘unknown symbols’ message during early boot.

Disclaimer

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