linux-kernel - Re: [PATCH 0/3] warn and suppress irqflood

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Message-ID: <871rhq7j1h.fsf@nanos.tec.linutronix.de>
Date:   Thu, 22 Oct 2020 10:37:46 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Pingfan Liu <kernelfans@...il.com>, linux-kernel@...r.kernel.org
Cc:     Pingfan Liu <kernelfans@...il.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Jisheng Zhang <Jisheng.Zhang@...aptics.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Guilherme G. Piccoli" <gpiccoli@...onical.com>,
        Petr Mladek <pmladek@...e.com>, Marc Zyngier <maz@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        afzal mohammed <afzal.mohd.ma@...il.com>,
        Lina Iyer <ilina@...eaurora.org>,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>,
        Maulik Shah <mkshah@...eaurora.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Jonathan Corbet <corbet@....net>,
        Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Oliver Neukum <oneukum@...e.com>, linux-doc@...r.kernel.org,
        kexec@...ts.infradead.org
Subject: Re: [PATCH 0/3] warn and suppress irqflood

On Thu, Oct 22 2020 at 13:56, Pingfan Liu wrote:
> I hit a irqflood bug on powerpc platform, and two years ago, on a x86 platform.
> When the bug happens, the kernel is totally occupies by irq.  Currently, there
> may be nothing or just soft lockup warning showed in console. It is better
> to warn users with irq flood info.
>
> In the kdump case, the kernel can move on by suppressing the irq flood.

You're curing the symptom not the cause and the cure is just magic and
can't work reliably.

Where is that irq flood originated from and why is none of the
mechanisms we have in place to shut it up working?

Thanks,

        tglx