Panic: attempted pmap_enter on 2MB page

[Alan Cox]

On Sat, Oct 2, 2010 at 9:11 PM, Dave Hayes <dave at jetcafe.org> wrote:

> What does the above mentioned panic mean? I'm booting from
> an mfsroot off of a DVD with a loader.conf like this:
>
>  autoboot_delay="5"
>  mfsroot_load="YES"
>  mfsroot_type="mfs_root"
>  mfsroot_name="/mfsboot"
>  vfs.root.mountfrom="ufs:md0"
>  vfs.root.mountfrom.options="rw"
>  kern.ipc.nmbclusters=32768
>  net.inet.tcp.tcbhashsize=16384
>  vm.pmap.pg_ps_enabled=1
>  vm.kmem_size="2G"
>  accf_http_load="YES"
>  net.inet.tcp.syncache.hashsize=1024
>  net.inet.tcp.syncache.bucketlimit=100
>
> This is FreeBSD 8.1-RELEASE amd64 running with the debugger installed
> into the kernel. Thanks in advance for any insight provided. :)
>

I'm afraid that I can't offer much insight without a stack trace.  At
initialization time, we map the kernel with 2MB pages.  I suspect that
something within the kernel is later trying to change one those mappings.
If I had to guess, it's related to the mfs root.

Regards,
Alan