How to debug kernel in bhyve?

[ahev]

Hello, I am doing kernel development and would like to debug my version of the kernel. Can I do that with the help of debugger and bhyve, to run in a containerized environment? Thanks.

 

[Cath O'Deray]

Seeking bhyve -G debug kernel found a CBSD page with byhve run through GDB; I guess it's also possible without CBSD.

 

[SirDice]

Add an extra "serial" port to the VM and configure remote serial debugging in the "test" kernel.

Chapter 10. Kernel Debugging

FreeBSD Kernel Debugging

docs.freebsd.org

 

[Andriy]

Add an extra "serial" port to the VM and configure remote serial debugging in the "test" kernel.

This is the way

 

[ahev]

Add an extra "serial" port to the VM and configure remote serial debugging in the "test" kernel.

Chapter 10. Kernel Debugging

FreeBSD Kernel Debugging

docs.freebsd.org

How to add the serial port to the VM? By using the -G option of /usr/share/examples/bhyve/vmrun.sh?

 

[Andriy]

How to add the serial port to the VM?

With -l option. bhyve(8) has explanation and examples.

 

[ahev]

Andriy in the manual, it says that
"The current debug server provides limited support for debuggers".
Does that mean there is an alternative way of launching remote gdb setup? Thanks.

 

[ahev]

https://docs.freebsd.org/en/books/developers-handbook/kerneldebug/#kerneldebug-online-gdb

Here in the handbook, unfortunately they don't describe what needs to be done to debug in bhyve, but the process is similar, correct?

 

[Andriy]

https://docs.freebsd.org/en/books/developers-handbook/kerneldebug/#kerneldebug-online-gdb

Here in the handbook, unfortunately they don't describe what needs to be done to debug in bhyve, but the process is similar, correct?

Yes, it is. The same, even. It does not matter where your FreeBSD is running as long as you can have serial port access.