Re: [PATCH sched/core] sched/rt: Fix RT_PUSH_IPI soft lockup loop

From: Tejun Heo

Date: Thu May 14 2026 - 00:49:02 EST


Hello,

On Wed, May 13, 2026 at 10:01:36PM -0400, Steven Rostedt wrote:
> I could try, but there are still some things that I don't understand.
> One is that to send more IPIs due to the RT pull request, there needs
> to be RT tasks constantly sleeping. Is that happening in this use case?
> Are the softirqs waking up RT tasks that run for a short time and go
> back to sleep, causing the pull IPI to trigger again?

Ah, yes, that makes sense. That's why the repro is using FIFO threads too.
In prod, there's mpi3mr threaded irq handlers that are FIFO. These are
storage machines so they're also constantly active.

Thanks.

--
tejun