The AMD machine check exception (MCE) code fix for Linux has landed ahead of this weekend’s anticipated 5.5-rc3 release. This AMD MCE fix allows for the AMD Ryzen Threadripper 3900 series processors introduced last month to boot the Linux kernel without hangs or other workarounds…

Source: Phoronix – Linux 5.5 Lands Fix For Booting New AMD Ryzen Threadripper Processors Without MCE Hang