Re: [PATCH REPOST] irq_poll: Add local_bh_disable() in cpu_dead notifier

[Christoph Hellwig]

On Tue, Feb 08, 2022 at 03:34:05PM +0100, Sebastian Andrzej Siewior wrote:
> __raise_softirq_irqoff() adds a bit to the pending sofirq mask and this
> is it. The softirq won't be handled in a deterministic way but randomly
> when an interrupt fires and handles the softirq in its irq_exit() routine or
> if something randomly checks and handles pending softirqs in the call
> chain before the CPU goes idle.
> 
> Add a local_bh_disable/enable() around the IRQ-off section which will
> handle pending softirqs.

And I still haven't seen any good explanation of why this is useful.