Error: "VMkernel Live Patch is incompatible due to lack of available read-only memory" during ESX 9.0 live patching

Products

• VMware vSphere ESXi

Issue/Introduction

With the release of ESX 9.0, the operating system supports updating kernel code, including the VMkernel as well as kernel modules, without rebooting the host. Such updates are delivered via Live Patch images; vLCM can apply such an image on hosts running an ESX base image that is compatible with the specific Live Patch image. See the Live Patch product documentation for more details.

When a Live Patch affects kernel code, vLCM performs certain prechecks on each host. During the compliance scan, the following error may be reported:

VMkernel Live Patch is incompatible due to lack of available read-only memory: <...> bytes free, <...> bytes required for patch modules <...>."

Environment

ESX 9.x

Cause

The host does not have enough read-only memory to load the patch's kernel module(s).

Resolution

None. The host must be remediated via reboot.

Additional Information

Live Patch product documentation: https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/9-0/managing-host-and-cluster-lifecycle/configuring-vlcm-remediation-settings-1/how-to-apply-live-patches-to-the-hosts-in-a-cluster-managed-with-images.html