linux-kernel - Re: [RFC PATCH] x86, mce: change the mce notifier to 'blocking' from 'atomic'

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Message-ID: <1492028744.2738.14.camel@intel.com>
Date:   Wed, 12 Apr 2017 20:27:05 +0000
From:   "Verma, Vishal L" <vishal.l.verma@...el.com>
To:     "bp@...e.de" <bp@...e.de>
CC:     "Williams, Dan J" <dan.j.williams@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-nvdimm@...ts.01.org" <linux-nvdimm@...ts.01.org>,
        "Luck, Tony" <tony.luck@...el.com>,
        "ross.zwisler@...ux.intel.com" <ross.zwisler@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>
Subject: Re: [RFC PATCH] x86, mce: change the mce notifier to 'blocking'
 from 'atomic'

On Wed, 2017-04-12 at 22:22 +0200, Borislav Petkov wrote:
> On Wed, Apr 12, 2017 at 01:59:03PM -0600, Vishal Verma wrote:
> > I don't think we can do anything about the panic path errors.
> 
> Then the fix should be a lot easier:
> 
> ---
> diff --git a/drivers/acpi/nfit/mce.c b/drivers/acpi/nfit/mce.c
> index 3ba1c3472cf9..44c092ec2ac9 100644
> --- a/drivers/acpi/nfit/mce.c
> +++ b/drivers/acpi/nfit/mce.c
> @@ -25,6 +25,9 @@ static int nfit_handle_mce(struct notifier_block
> *nb, unsigned long val,
>  	struct acpi_nfit_desc *acpi_desc;
>  	struct nfit_spa *nfit_spa;
>  
> +	if (in_atomic())
> +		return NOTIFY_DONE;

But isn't the atomic notifier call chain always called in atomic
context?

> +
>  	/* We only care about memory errors */
>  	if (!(mce->status & MCACOD))
>  		return NOTIFY_DONE;
> 
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton,
> HRB 21284 (AG Nürnberg)