Re: kernel crash: devctl set driver -f mlx5_core6 ppt

From: Konstantin Belousov <kostikbel_at_gmail.com>
Date: Fri, 29 Sep 2023 15:24:17 UTC 
On Fri, Sep 29, 2023 at 04:32:30AM +0000, John wrote:
> Hi Folks,
> 
>    Working against 13.2-STABLE.
> 
>    I have a chance to get some bhyve VMs running on new hardware
> with Mellanox 100Gb/s cards. After creating VF entries with iovctl
> at boottime, a devctl command to detach the mlx5 driver and attach
> the ppt driver causes the kernel to crash:
> 
>  # devctl set driver -f mlx5_core6 ppt
> 
> backtrace here: https://people.freebsd.org/~jwd/mlx5.dump.txt
What is the line number for pci_iov_detach_method+0x5e?
Better, load vmcore into debugger and get the backtrace from kgdb.

> 
>    If I create the VF in ppt mode I can correctly detach
> the ppt driver and attach the mlx5 driver.
> 
>    Also of note, if multiple VFs are created and a single
> VF is targeted for the detach operation, all VFs are operated
> on. It seems the VFs are not seen as individual entities
> but a group of children in detach_method().