linux-kernel - Re: [PATCH] x86/nmi: Remove the 'strange power saving mode' hint from unknown NMI handler

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Date:   Mon, 14 Mar 2022 11:59:00 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Jiri Kosina <jikos@...nel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/nmi: Remove the 'strange power saving mode' hint
 from unknown NMI handler

On Mon, Mar 14, 2022 at 09:25:18AM +0100, Jiri Kosina wrote:
> From: Jiri Kosina <jkosina@...e.cz>
> 
> The 'Do you have a strange power saving mode enabled?' hint when unknown 
> NMI happens dates back to i386 stone age, and isn't currently really 
> helpful.
> 
> Unknown NMIs are coming for many different reasons (broken firmware, 
> faulty hardware, ...) and rarely have anything to do with 'strange power 
> saving mode' (whatever that even is).
> 
> Just remove it as it's largerly misleading.
> 
> Signed-off-by: Jiri Kosina <jkosina@...e.cz>

Fair enough,

Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>

> ---
>  arch/x86/kernel/nmi.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
> index 4bce802d25fb..e73f7df362f5 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -292,7 +292,6 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
>  	pr_emerg("Uhhuh. NMI received for unknown reason %02x on CPU %d.\n",
>  		 reason, smp_processor_id());
>  
> -	pr_emerg("Do you have a strange power saving mode enabled?\n");
>  	if (unknown_nmi_panic || panic_on_unrecovered_nmi)
>  		nmi_panic(regs, "NMI: Not continuing");
>  
> -- 
> Jiri Kosina
> SUSE Labs
>