[Crash-utility] The problems when running SuSE 12 on VirtualBox

[Dave Anderson]

----- Original Message -----
> > 
> > So my questions are:
> > 
> > (1) Is it OK to use "/proc/kcore" instead of "/dev/mem" as a workaround?
> > Is there any side-effect?
> 
> As I read it, /proc/kcore is the kernel's virtual address space and
> /dev/mem is the system's physical address space. It probably isn't wise
> to debug the latter on any dom0 (whether nested in another
> virtualization or not) except in very acute cases. It may explain the
> problem you were having in the first place if VirtualBox affects whether
> /dev/mem is a real physical memory view or if it doesn't then whether
> VirtualBox itself affects those cases where, as I understand it, the
> kernel has constant physical addresses for some things.

Hi Dave,

I'm not sure why /proc/kcore should be considered unwise?  Even with a Xen
dom0 kernel, if it works, it works.  All that crash is doing is taking the
physical address it normally would use for reading from /dev/mem (or /dev/crash),
and turning it into a unity-mapped kernel virtual address that it reads from
/proc/kcore.  I might be missing something, but it would seem like the 
virtualization aspect would be a non-issue?

/proc/kcore is a problem with 32-bit kernels, which cannot unity-map physical
memory above 896MB, but even with those, the session still comes up, albeit
slightly crippled.  

Dave