Re: r270287: crash

On Aug 21, 2014, at 12:26 PM, O. Hartmann <ohartman_at_zedat.fu-berlin.de> wrote:

> FreeBSD r270287 crashes/reboots instantanously on loading the kernel. I
> can not see at what point (on modern systems like Ivy Bridge). On older
> Core2Duo systems I get a trap 12 in APIC or similar.
> 
> While I was able to start kernel.old on the modern systems, I fail on
> both kernel and kernel.old on the C2D system.
> 
> I'd like to know whether there is a way to save the system I can not
> reboot the on-disk kernels snce they are, woderfull, compromised.
> 
> Is there a possible scenario  like:
> 
> a) boot from DVD ROM or USB most recent snapshot
> b) establish network with on-disk config, svn checkout recent sources
> into on-disk file hierarchy
> c) build repaired/patched kernel and install on on-disk (not on the
> emergency boot media).

I would grab a snapshot ISO or USB disk image: ftp://ftp.freebsd.org/pub/FreeBSD/snapshots/amd64/amd64/ISO-IMAGES/11.0/ . After that you can mount your filesystems, revert to an earlier SVN revision, and repair your system that way. You could also copy over the  /boot/kernel as long as you didn’t have/need any customizations.

> Thanks, help appreciated and what is about this crash affecting recent
> CURRENT r270287, what has corrupted the system?

That’s a better question. Booting off newer sources worked on my VM at least, but it’s not real hardware. Maybe something dealing with vt(4)/xen?
HTH!
-Garrett