Re: [PATCH 0000/2297] [ANNOUNCE, RFC] "Fast Kernel Headers" Tree -v1: Eliminate the Linux kernel's "Dependency Hell"

From: Ingo Molnar
Date: Tue Jan 04 2022 - 19:40:38 EST



* Nathan Chancellor <nathan@xxxxxxxxxx> wrote:

> > I.e. I think the bug was simply to make main.c aware of the array, now
> > that the INIT_THREAD initialization is done there.
>
> Yes, that seems right.
>
> Unfortunately, while the kernel now builds, it does not boot in QEMU. I
> tried to checkout at 9006a48618cc0cacd3f59ff053e6509a9af5cc18 to see if I
> could reproduce that breakage there but the build errors out at that
> change (I do see notes of bisection breakage in some of the commits) so I
> assume that is expected.

Yeah, there's a breakage window on ARM64, I'll track down that
bisectability bug.

Decoupling thread_info and task_struct incrementally, so that it bisects
cleanly on all architectures, was always a big challenge. :-/

> There is no output, even with earlycon, so it seems like something is
> going wrong in early boot code. I am not very familiar with the SCS code
> so I will see if I can debug this with gdb later (I'll try to see if it
> is reproducible with GCC as well; as Nick mentions, there is support
> being added to it and I don't mind building from source).

Just to make sure: with SCS disabled the same kernel boots fine?

> Sure thing, I will continue to follow this and test it as much as I can
> to make sure everything continues to work well!

Thank you!

Ingo