Re: KVM 29: Page fault in kernel mode while booting GNU/kFreeBSD

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Aurelien Jarno wrote:
> Hi,
>
> I have just updated my system from kvm 28 to kvm 29, and a GNU/kFreeBSD
> amd64 system fails to boot with the following error:
>
>   Fatal trap 12 with interrupts disabled
>
>
>   Fatal trap 12: page fault while in kernel mode
>   fault virtual address   = 0x7aa93e0
>   fault code              = supervisor read, page not present
>   instruction pointer     = 0x8:0xffffffff80598b36
>   stack pointer           = 0x10:0xffffffff87c556b0
>   frame pointer           = 0x10:0xffffff0007aa9260
>   code segment            = base 0x00, lmit 0xfffff, type 0x1b
>                           = DPL 0, pres 1, long 1, def32 0, gran 1
>   processor eflags        = resume, IOPL = 0
>   current process         = 1 (init)
>   trap number             = 12
>   panic: page fault
>
>
> This is on an machine with an Athlon64 X2 CPU.
>
> As it was running fine with kvm 28, I tried to mix kvm 28 and kvm 29. It
> fails when using modules from kvm 29, whatever the version of the
> userland part. This looks like a problem in the kernel modules.
>
> Please also note that GNU/kFreeBSD i386 is working fine with kvm 29 on
> the same machine.
>
> Please tell me what I can do to help debugging this problem. 
> Alternatively I have uploaded an image to reproduce the problem here:
> http://temp.aurel32.net/kfreebsd-amd64.img.gz
>
>   

Can you bisect kvm to find the offending commit?  Basically, you do a

  git clone git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm.git
  cd kvm
  git bisect start drivers/kvm/
  bit bisect bad kvm-29
  git bisect good kvm-28

git will check out a test candidate; go to your kvm userspace directory 
and do

  make -C kernel sync LINUX=/path/to/the/kvm/git/directory
  make -C kernel
  sudo make -C kernel install

reload the module, test, and issue 'git bisect good' or 'git bisect bad' 
according to the result.  As there are only 25 commits you should be 
done in 5 cycles.

-- 
error compiling committee.c: too many arguments to function


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