Build failure with verify size in next-20171102

[tony@atomide.com (Tony Lindgren)]

* Russell King - ARM Linux <linux@armlinux.org.uk> [171102 23:22]:
> On Thu, Nov 02, 2017 at 12:30:27PM -0700, Tony Lindgren wrote:
> > Hi Russeell,
> > 
> > I think you're already aware of the build failure caused by commit
> > 078c0927485e ("ARM: verify size of zImage"), but here's info just
> > in case.
> > 
> > arm-unknown-linux-musleabi-ld.bfd: error: zImage file size is incorrect
> > make[2]: *** [arch/arm/boot/compressed/Makefile:185: arch/arm/boot/compressed/vmlinux] Error 1
> > make[1]: *** [arch/arm/boot/Makefile:64: arch/arm/boot/compressed/vmlinux] Error 2
> > make: *** [arch/arm/Makefile:335: zImage] Error 2
> > 
> > Other than that I was surprised that next actually booted for me
> > after a few week break with Linux next! :)
> 
> It would be nice if people can investigate why that happens - I'm
> completely unable to reproduce it locally, even if I link using 
> the same vmlinux.lds file and the objects from someone who sees the
> failure.
> 
> There's some binutils version specific stuff that's going on here.
> 
> What I have in my current for-next, which I'm intending to push,
> is all the same patches except the patch that introduces the above
> check is subsituted by a patch that produces an extra _edata_real
> symbol.  This _should_ match _edata.  So, if you hit this failure,
> try either my current for-next branch or tomorrow's linux-next, and
> run arm-linux-nm on arch/arm/boot/compressed/vmlinux and check the
> addresses given for _edata and _edata_real.

OK thanks reverting 078c0927485e and applying dad4675388fc ("ARM:
add debug ".edata_real" symbol") from your for-next branch builds
and boots for me.

> Theory says they should be identical, but the failure of that assert
> could only happen if "." inside the output section was different from
> _edata assigned outside.  _edata_real is now the address of "." inside
> the output section.

With 078c0927485e reverted and dad4675388fc applied they are
identical for me:

$ ${armcompiler}nm arch/arm/boot/compressed/vmlinux | grep _edata
00421960 D _edata
00421960 D _edata_real

Let me know if you want me to run some test with the failing
commit also.

Regards,

Tony