Messages in this thread | | | Date | Tue, 3 Jul 2018 23:26:09 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: 4.17.x won't boot due to "x86/boot/compressed/64: Handle 5-level paging boot if kernel is above 4G" |
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On Tue, Jul 03, 2018 at 11:03:07AM -0700, Andi Kleen wrote: > On Tue, Jul 03, 2018 at 05:21:50PM +0300, Kirill A. Shutemov wrote: > > On Tue, Jul 03, 2018 at 03:44:03PM +0300, Kirill A. Shutemov wrote: > > > On Tue, Jul 03, 2018 at 01:24:49PM +0200, Gabriel C wrote: > > > > 2018-07-01 23:32 GMT+02:00 Benjamin Gilbert <bgilbert@redhat.com>: > > > > > On Sun, Jul 01, 2018 at 05:15:59PM -0400, Benjamin Gilbert wrote: > > > > >> 4.17 kernels built with the CoreOS Container Linux toolchain and kconfig, > > > > >> up to and including 4.17.3, fail to boot on AMD64 running in (at least) > > > > >> QEMU/KVM. No messages are shown post-GRUB; the VM instantly reboots. > > > > >> Reverting commit 194a9749c73d ("x86/boot/compressed/64: Handle 5-level > > > > >> paging boot if kernel is above 4G") fixes it. I've attached our kernel > > > > >> config for reference, and am happy to test patches, provide sample QCOW > > > > >> images, etc. > > > > > > > > > > > > > Also see https://bugzilla.kernel.org/show_bug.cgi?id=200385 , > > > > > > > > 0a1756bd2897951c03c1cb671bdfd40729ac2177 is acting up > > > > too with the same symptoms > > > > > > I tracked it down to -flto in LDFLAGS. I'll look more into this. > > > > -flto in LDFLAGS screws up this part of paging_prepare(): > > Where is that coming from? The LTO patches are not upstream. > > And I don't see any LTO usage in the main line.
Apparently some distros try to hack it around:
https://bugzilla.kernel.org/show_bug.cgi?id=200385
I'm amazed that it kinda worked for them.
> > /* Copy trampoline code in place */ > > memcpy(trampoline_32bit + TRAMPOLINE_32BIT_CODE_OFFSET / sizeof(unsigned long), > > &trampoline_32bit_src, TRAMPOLINE_32BIT_CODE_SIZE); > > > > In particular, relocation for trampoline_32bit_src solved in the wrong > > way. Without -flto, we have rip-realtive address load: > > > > 982d30: 48 8d 35 09 cc ff ff lea -0x33f7(%rip),%rsi # 97f940 <trampoline_32bit_src> > > > > With -flto we have immediate load: > > > > 982cf0: 48 c7 c6 f0 f8 97 00 mov $0x97f8f0,%rsi > > Strange. > > Can you add some RELOC_HIDE()s and see if that helps?
Nope. No difference in generated code.
-- Kirill A. Shutemov
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