12.1-prerelease nullfs? related panic

[Christos Chatzaras]

> 
> This occured only once and after the reboot, I found a corrupted file on my nullfs-mount.  It wasn't mutilated, but showed content of another valid file in the same directory (like 'cat fil1 >> vfile2')
> 
> Any ideas if this has been recently addressed since 09/09?
> 

Maybe we have the same issue, but I am not sure as the servers rebooted and I don't have a crash dump:

https://lists.freebsd.org/pipermail/freebsd-stable/2019-September/091503.html <https://lists.freebsd.org/pipermail/freebsd-stable/2019-September/091503.html>

I use nullfs mounts too for 3 jails on each server.

The issue happened in 5 servers (total servers 63) 5-6 hours after I upgrade from r351639 to r352091, but I am sure it would happen to all servers after some time if I didn't reboot them to r351639 kernel.