Re: 4.17.x won't boot due to "x86/boot/compressed/64: Handle 5-level paging boot if kernel is above 4G"

[Kirill A. Shutemov]

On Tue, Jul 03, 2018 at 11:10:27PM -0400, Benjamin Gilbert wrote:
> On Tue, Jul 03, 2018 at 05:21:50PM +0300, Kirill A. Shutemov wrote:
> > I don't know how to solve it. As far as I know we don't support compiling
> > kernel with LTO in mainline.
> > 
> > Any suggestions?
> > 
> > Benjamin, do you change LDFLAGS or CFLAGS when compiling the kernel?
> 
> We're using the standard build flags as far as I can tell.  In particular,
> we don't enable LTO, and I've verified that -flto isn't in the build logs.
> 
> Here's a sample image:
> 
> https://users.developer.core-os.net/bgilbert/4.17/vmlinuz-4.17.3-coreos
> https://users.developer.core-os.net/bgilbert/4.17/vmlinux-4.17.3-coreos
> https://users.developer.core-os.net/bgilbert/4.17/System.map

It's basically the same issue. We have immidiate load instead of
RIP-relative address load.

You can make the vmlinuz bootable with this binary patch:

echo -en "\x8d\x05\xa9\xa9\xff\xff" | dd of=vmlinuz-4.17.3-coreos seek=$((0x005d1fc1)) bs=1 conv=notrunc

Now we need to find out how linker gets it wrong.

Please, *after* complete build of the kernel with your toolchain do this:

touch arch/x86/boot/compressed/pgtable_64.c
make V=1

And share your build log.

-- 
 Kirill A. Shutemov