how to determine whether the source code is same between two kernels

[greg kh]

On Wed, May 08, 2019 at 05:43:02PM +0800, wuzhouhui wrote:
> > -----Original Messages-----
> > From: "Greg KH" <greg at kroah.com>
> > Sent Time: 2019-05-08 17:25:54 (Wednesday)
> > To: wuzhouhui <wuzhouhui14 at mails.ucas.ac.cn>
> > Cc: kernelnewbies at kernelnewbies.org
> > Subject: Re: how to determine whether the source code is same between two kernels
> > 
> > On Wed, May 08, 2019 at 04:52:46PM +0800, wuzhouhui wrote:
> > > Hi,
> > > 
> > > Suppose I have two kernels, one is A.B.C build by people Tom. And
> > > the other is A.B.C build by Jerry. The source code have been deleted
> > > after kernel is build and installed. Now I want to know whether the
> > > source code of these two kernel is the same (even if they have the same
> > > name). All I have is binaries (e.g. vmlinux, config, *.ko, System.map).
>                                         ^^^^^^^
>                                         vmlinuz, sorry for the typo.
> > > Is it possible?
> 
> Using word "same" is too strict. At least, I want to know the source code of
> two kernels is "equivalent". I already know that the source code is equivalent
> if the srcversion of two modules is same (correct me if it is wrong). Does
> vmlinuz has srcversion too?

What do you mean by "srcversion"?

The only way you "know" for sure that any two trees is either looking at
the source code, or by generating a binary that is identical from one
tree that you can compare to the other one.

thanks,

greg k-h