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

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Message-ID: <20170412211302.3d2cxe34sgiu3dag@pd.tnic>
Date:   Wed, 12 Apr 2017 23:13:03 +0200
From:   Borislav Petkov <bp@...e.de>
To:     "Verma, Vishal L" <vishal.l.verma@...el.com>
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, Apr 12, 2017 at 08:27:05PM +0000, Verma, Vishal L wrote:
> But isn't the atomic notifier call chain always called in atomic
> context?

No, it isn't. We're calling it in normal process context in
mce_gen_pool_process() too.

So this early exit will avoid any sleeping in atomic context. And since
there's nothing you can do about the errors reported in atomic context,
we can actually use that fact.

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--