linux-kernel - Re: [PATCH] x86/nmi: remove the irqwork from long duration nmi handler

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Message-ID: <877e20bb8o.fsf@nanos.tec.linutronix.de>
Date:   Thu, 09 Jan 2020 21:55:51 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Changbin Du <changbin.du@...il.com>
Cc:     Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        hpa@...or.com, x86@...nel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, Changbin Du <changbin.du@...il.com>
Subject: Re: [PATCH] x86/nmi: remove the irqwork from long duration nmi handler

Changbin Du <changbin.du@...il.com> writes:

> First, printk is NMI context safe now since the safe printk has been
> implemented. The safe printk already has an irqwork to make NMI context
> safe.
>
> Second, the NMI irqwork actually does not work if a NMI handler causes
> panic by watchdog timeout. This NMI irqwork have no chance to run in such
> case, while the safe printk will flush its per-cpu buffer before panic.
>
> Signed-off-by: Changbin Du <changbin.du@...il.com>

Looks about right.

Acked-by: Thomas Gleixner <tglx@...utronix.de>