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Date: Thu, 6 Jun 2019 14:46:43 -0700
From: Andrew Morton <akpm@...ux-foundation.org>
To: Dan Williams <dan.j.williams@...el.com>
Cc: stable@...r.kernel.org, linux-mm@...ck.org,
linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org,
osalvador@...e.de, mhocko@...e.com
Subject: Re: [PATCH v9 11/12] libnvdimm/pfn: Fix fsdax-mode namespace
info-block zero-fields
On Wed, 05 Jun 2019 14:58:58 -0700 Dan Williams <dan.j.williams@...el.com> wrote:
> At namespace creation time there is the potential for the "expected to
> be zero" fields of a 'pfn' info-block to be filled with indeterminate
> data. While the kernel buffer is zeroed on allocation it is immediately
> overwritten by nd_pfn_validate() filling it with the current contents of
> the on-media info-block location. For fields like, 'flags' and the
> 'padding' it potentially means that future implementations can not rely
> on those fields being zero.
>
> In preparation to stop using the 'start_pad' and 'end_trunc' fields for
> section alignment, arrange for fields that are not explicitly
> initialized to be guaranteed zero. Bump the minor version to indicate it
> is safe to assume the 'padding' and 'flags' are zero. Otherwise, this
> corruption is expected to benign since all other critical fields are
> explicitly initialized.
>
> Fixes: 32ab0a3f5170 ("libnvdimm, pmem: 'struct page' for pmem")
> Cc: <stable@...r.kernel.org>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>
The cc:stable in [11/12] seems odd. Is this independent of the other
patches? If so, shouldn't it be a standalone thing which can be
prioritized?
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