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Date: Tue, 5 Jun 2018 16:11:04 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm <linux-nvdimm@lists.01.org>, linux-edac@vger.kernel.org,
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	Christoph Hellwig <hch@lst.de>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Matthew Wilcox <mawilcox@microsoft.com>,
	Ingo Molnar <mingo@redhat.com>,
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	Souptick Joarder <jrdr.linux@gmail.com>,
	Linux MM <linux-mm@kvack.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v2 00/11] mm: Teach memory_failure() about ZONE_DEVICE
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On Mon 04-06-18 07:31:25, Dan Williams wrote:
[...]
> I'm trying to solve this real world problem when real poison is
> consumed through a dax mapping:
> 
>         mce: Uncorrected hardware memory error in user-access at af34214200
>         {1}[Hardware Error]: It has been corrected by h/w and requires
> no further action
>         mce: [Hardware Error]: Machine check events logged
>         {1}[Hardware Error]: event severity: corrected
>         Memory failure: 0xaf34214: reserved kernel page still
> referenced by 1 users
>         [..]
>         Memory failure: 0xaf34214: recovery action for reserved kernel
> page: Failed
>         mce: Memory error not recovered
> 
> ...i.e. currently all poison consumed through dax mappings is
> needlessly system fatal.

Thanks. That should be a part of the changelog. It would be great to
describe why this cannot be simply handled by hwpoison code without any
ZONE_DEVICE specific hacks? The error is recoverable so why does
hwpoison code even care?

-- 
Michal Hocko
SUSE Labs