Re: lapic-related boot crash in 4.15-rc1

From: Thomas Gleixner
Date: Wed Jan 10 2018 - 13:34:27 EST


On Wed, 10 Jan 2018, Meelis Roos wrote:
> On 3 of my test computers, boot hangs with 4.15 git kernels. So far I
> have traced it down to 4.14.0 being good and 4.15-rc1 being bad (bisect
> is slow because the computers are somwehat remote). Also because of
> trying to find when it started, I have not tries newer than rc5
> kernels.
>
> The hang happens after Performance Events feature table has been printed
> but before APIC initialization messages normally appear ("Enabling APIC
> mode: Flat. Using 0 I/O APICs" or something like that).
>
> It happens on at least 3 distinct computers:
> * AMD Athlon with AMD 750 chipset
> * P3 1 GHz with i815 chipset
> * P4 1.7 GHz with SiS chipset
>
> They all have have "lapic" parameter because they were telling me that
> lapic has been disabled by BIOS and I re-enabled it with the parameter
> to get apic timer interrupts. This worked up until 4.14.
>
> None of the computers have IO-APICs.

Oh. Then it possibly falls into Dou's realm.

Dou?

Thanks,

tglx