Sender: Ingo Molnar <mingo.kernel.org@gmail.com>
Date:   Wed, 5 Jan 2022 01:40:32 +0100
From:   Ingo Molnar <mingo@kernel.org>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "David S. Miller" <davem@davemloft.net>,
        Ard Biesheuvel <ardb@kernel.org>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Al Viro <viro@zeniv.linux.org.uk>, llvm@lists.linux.dev
Subject: Re: [PATCH 0000/2297] [ANNOUNCE, RFC] "Fast Kernel Headers" Tree
 -v1: Eliminate the Linux kernel's "Dependency Hell"
Message-ID: <YdTpAJxgI+s9Wwgi@gmail.com>
References: <YdIfz+LMewetSaEB@gmail.com>
 <YdM4Z5a+SWV53yol@archlinux-ax161>
 <YdQlwnDs2N9a5Reh@gmail.com>
 <YdSI9LmZE+FZAi1K@archlinux-ax161>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YdSI9LmZE+FZAi1K@archlinux-ax161>
Precedence: bulk


* Nathan Chancellor <nathan@kernel.org> 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