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From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>,
	"Herton R. Krzesinski" <herton@redhat.com>
Cc: linux-kernel@vger.kernel.org, frederic@kernel.org,
	mingo@kernel.org, paulmck@linux.vnet.ibm.com,
	anna-maria@linutronix.de, kyin@redhat.com, jaeshin@redhat.com
Subject: Re: [RFC] Processing of raised_list can stall if an IPI/interrupt is missed
Date: Tue, 03 Mar 2026 23:39:39 +0100	[thread overview]
Message-ID: <878qc8zges.ffs@tglx> (raw)
In-Reply-To: <20260303192953.GM1395266@noisy.programming.kicks-ass.net>

On Tue, Mar 03 2026 at 20:29, Peter Zijlstra wrote:

> On Tue, Mar 03, 2026 at 04:07:15PM -0300, Herton R. Krzesinski wrote:
>
>> Or may be it's not worth changing this since this is rare and missed self IPI should
>> not be expected?
>
> IPIs going missing is certainly unexpected; although kernel/smp.c has
> much debugging crud for similar scenarios (AFAIK all of them related to
> virt).
>
> If IPIs go missing your system *will* go funny in one way or another.
> I'm not totally against building in some fallback, but we should
> definitely consider it dodgy/buggy if we do detect one has gone
> walk-about.

Indeed and there is enough code by now which relies on the pristine IPI
context when the architecture supports it, so basically reverting this
change is going to create a boatload of other hard to debug problems.

Thanks

        tglx

  reply	other threads:[~2026-03-03 22:39 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-03 19:07 [RFC] Processing of raised_list can stall if an IPI/interrupt is missed Herton R. Krzesinski
2026-03-03 19:29 ` Peter Zijlstra
2026-03-03 22:39   ` Thomas Gleixner [this message]
2026-03-04 13:12     ` Herton Krzesinski

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