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Date: Mon, 13 Jul 2026 18:10:01 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Bradley Morgan <include@grrlz.net>
Cc: brauner@kernel.org, peterz@infradead.org, oleg@redhat.com,
 tglx@kernel.org, npiggin@gmail.com, ebiederm@xmission.com,
 pasha.tatashin@soleen.com, kees@kernel.org, stable@vger.kernel.org,
 linux-kernel@vger.kernel.org,
 syzbot+8fdf0d8e10bdde1c2e88@syzkaller.appspotmail.com
Subject: Re: [PATCH] reboot: use make_task_dead for the halt and power off
 fallback
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On Mon, 13 Jul 2026 06:23:32 +0000 Bradley Morgan <include@grrlz.net> wrote:

> The reboot syscall calls do_exit(0) after kernel_halt() or
> kernel_power_off().  Those are expected to stop the machine and not
> return.  When they do return, the shutdown path has already disabled
> interrupts and torn down state, and do_exit() then hits its
> WARN_ON(irqs_disabled()).

Well...  why are they returning?  Is it both kernel_halt() and
kernel_power_off()?  The report seems to indicate that
kernel_power_off() is returning.

So is there a flaw in x86 machine_power_off() which we should be
addressing?

> That is an error path, not a clean exit.  Use make_task_dead() instead
> of do_exit(0): it is built for this, fixes up the irqs disabled and
> preempt state, and bounds repeated failure via oops_limit.  This
> matches the make_task_dead pattern that exit.c already uses for the
> oops path.

And make_tsk_dead() is __noreturn.