Hi Paul,

On Wed, Mar 19, 2014 at 02:09:00PM -0400, Paul Gortmaker wrote:
> On 14-03-19 06:45 AM, Fengguang Wu wrote:
> > FYI.
> > 
> > The first bad commit is probably a bug fix that unveils the link errors.
> 
> Yes, kvm doesn't build if you checkout 9a15c944f76cffa55~1
> But if you disable kvm/paravirt/guest in your .config, then
> you will see the same i2c link error.  I tried building the
> prev. release (v.2.6.39) but my gcc was simply too new for
> such an ancient kernel. 
>  
> > tree:   git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> > head:   9a15c944f76cffa5581959cefe709c7c4ea26994
> > commit: 9dac77fa4011bdb4b541a8db087eac96a602faec KVM: x86 emulator: fold decode_cache into x86_emulate_ctxt
> > date:   2 years, 8 months ago
> > config: i386-randconfig-xb0-03190932 (attached as .config)
> > 
> > All error/warnings:
> > 
> >    drivers/built-in.o: In function `mb862xx_i2c_init':
> >>> (.text+0x8c0aa): undefined reference to `i2c_add_adapter'
> >    drivers/built-in.o: In function `mb862xx_i2c_exit':
> >>> (.text+0x8c13a): undefined reference to `i2c_del_adapter'
> 
> Do you have a .config that exhibits the same fail on master?
> The 3.0 config you've attached, after an "oldconfig" doesn't
> fail for me on master.

Yes, attached is the .config for linus/master. I confirmed that it can
reproduce the link errors on it:

  MODPOST vmlinux.o
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  LD      init/built-in.o
drivers/built-in.o: In function `mb862xx_i2c_init':
(.text+0xc1ffe): undefined reference to `i2c_add_adapter'
drivers/built-in.o: In function `mb862xx_i2c_exit':
(.text+0xc208a): undefined reference to `i2c_del_adapter'
make[1]: *** [vmlinux] Error 1
make: *** [sub-make] Error 2

gcc (Debian 4.6.3-1) 4.6.3

Thanks,
Fengguang