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Date: Wed, 22 Mar 2023 16:03:11 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: <linux-fsdevel@vger.kernel.org>, <nvdimm@lists.linux.dev>,
 <dan.j.williams@intel.com>, <willy@infradead.org>, <jack@suse.cz>,
 <djwong@kernel.org>
Subject: Re: [PATCH] fsdax: unshare: zero destination if srcmap is HOLE or
 UNWRITTEN
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References: <1679483469-2-1-git-send-email-ruansy.fnst@fujitsu.com>
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On Wed, 22 Mar 2023 11:11:09 +0000 Shiyang Ruan <ruansy.fnst@fujitsu.com> wrote:

> unshare copies data from source to destination. But if the source is
> HOLE or UNWRITTEN extents, we should zero the destination, otherwise the
> result will be unexpectable.

Please provide much more detail on the user-visible effects of the bug.
For example, are we leaking kernel memory contents to userspace?

Thanks.