When the kdump kernel is booted, the following error will appear in the boot log:
/dev/efirtc: No such file or directory
This error results from a malformed request to create the efirtc in an incorrect path. However, the device path in question is also created statically in the initramfs when the kdump service is started. As such, the run-time creation of the device node is redundant, harmless, and should not affect the performance of kdump.