The einj_error_inject function in drivers/acpi/apei/einj.c in the Linux kernel allows local users to simulate hardware errors and consequently cause a denial of service by leveraging failure to disable APEI error injection through EINJ when securelevel is set.
https://github.com/mjg59/linux/commit/d7a6be58edc01b1c66ecd8fcc91236bfbce0a420