linux-kernel - RE: [PATCH v1 2/4] x86/mce: dump error msg from severities

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Message-ID: <SJ1PR11MB6083726C2A8951777CCE15B1FCFE2@SJ1PR11MB6083.namprd11.prod.outlook.com>
Date: Fri, 14 Feb 2025 16:57:33 +0000
From: "Luck, Tony" <tony.luck@...el.com>
To: Shuai Xue <xueshuai@...ux.alibaba.com>, "bp@...en8.de" <bp@...en8.de>,
	"nao.horiguchi@...il.com" <nao.horiguchi@...il.com>
CC: "tglx@...utronix.de" <tglx@...utronix.de>, "mingo@...hat.com"
	<mingo@...hat.com>, "dave.hansen@...ux.intel.com"
	<dave.hansen@...ux.intel.com>, "x86@...nel.org" <x86@...nel.org>,
	"hpa@...or.com" <hpa@...or.com>, "linmiaohe@...wei.com"
	<linmiaohe@...wei.com>, "akpm@...ux-foundation.org"
	<akpm@...ux-foundation.org>, "linux-edac@...r.kernel.org"
	<linux-edac@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org>,
	"baolin.wang@...ux.alibaba.com" <baolin.wang@...ux.alibaba.com>,
	"tianruidong@...ux.alibaba.com" <tianruidong@...ux.alibaba.com>
Subject: RE: [PATCH v1 2/4] x86/mce: dump error msg from severities

> > This is called from the #MC handler. Is that a safe context to print a console
> > message? It wasn't in the past, but maybe changes to how console messages
> > are handled have changed this.
> >
> > -Tony
>
> #MC is a kind of NMI context, as far as I know, since
>
> commit 42a0bb3f71383b457a7db362f1c69e7afb96732b
> printk/nmi: generic solution for safe printk in NMI
>
> print a console message is safe.
>
> Please correct me if I missed anything.

wow, that's v4.7 (ancient history). I thought I'd had issues with debug
messages in the machine check handler more recently than that, but
perhaps I'm misremembering.

-Tony