Re: 4.14.9 doesn't boot (regression)

[Linus Torvalds]

On Fri, Dec 29, 2017 at 1:02 PM, Toralf FÃrster <toralf.foerster@xxxxxx> wrote:
> On 12/29/2017 09:12 PM, Linus Torvalds wrote:
>> instead, and see if that makes a difference, that would narrow down
>> the possible root cause of this problem.
>
> not at this ThinkPad T440s (didn't test at the server with an i7-3930).
>
> Boot stops just at:
>
>         tsc: Refined TSC clocksource calibration: 2494.225 MHz
>         clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x23f3ea95b09, max_idle_ns: 440795287034 ns

Uhhuh. So for Alexander Troy, just getting rid of the -march=core2
fixed the boot.

But not for you.

Strange. It really looked like the exact same thing.

> This is a "Intel(R) Core(TM) i5-4300U CPU @ 1.90GHz" with gcc-6.4

Yeah, other reporters of this have used gcc-6.4.0 too.

But there's been some muddying of the waters there too - changing
compilers have fixed it for some cases, but there's at least one
report that a kernel build with gcc-7.2.0 still had the issue (and
another that said it didn't).

But the MCORE2 was consistent for several people - including you.
Until this point.

Strange.

The only other thing (apart from the compiler flag) that MCORE2
results in is to enable

 CONFIG_X86_INTEL_USERCOPY
 CONFIG_X86_USE_PPRO_CHECKSUM
 CONFIG_X86_P6_NOP

and the two first of those shouldn't even matter on x86-64, and I
don't see that last one making any difference either.

So because it looks so impossible that the "-march=core2" didn't make
a difference for you, I'll ask you to please double-check that you
actually booted into the right kernel.

Sorry for doubting you, but your report just broke the _one_
consistent thing we've seen about this bug.

              Linus