BUG Bad page state in process kswapd0 pfn09e23 Error

The reason you're seeing this when you launch the Lish console is because Lish shows output from dmesg, which shows messages from the kernel ring buffer. You can hit the Enter key to get a login prompt if one doesn't appear for you. Once you're logged in, you can run dmesg -D to disable dmesg output if you'd like. More information about dmesg and Lish can be found in this Linode Community Questions site post.

I did some searching on that specific message and it looks like there are a few potential causes. One possible fix would be to change your Linode's kernel if you find that it's a recurring issue or that it's causing your Linode to crash. If you have more information about what your Linode is doing when you see that message, that would be helpful so the Linode Community can take a closer look.