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From: "Darrick J. Wong" <djwong@kernel.org>
To: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev,
	dan.j.williams@intel.com, willy@infradead.org, jack@suse.cz
Subject: Re: [PATCH] fsdax: unshare: zero destination if srcmap is HOLE or UNWRITTEN
Date: Thu, 23 Mar 2023 07:59:57 -0700	[thread overview]
Message-ID: <20230323145957.GA466461@frogsfrogsfrogs> (raw)
In-Reply-To: <a41f0ea1-c704-7a2e-db6d-93e8bd4fcdea@fujitsu.com>

On Thu, Mar 23, 2023 at 02:50:38PM +0800, Shiyang Ruan wrote:
> 
> 
> 在 2023/3/23 7:03, Andrew Morton 写道:
> > 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?
> 
> This fixes fail of generic/649.

Please make a note of easy(ish) reproducers when you know about them,
e.g.

"Found by running generic/649 while mounting with -o dax=always on
pmem."

So that anyone scanning around for fix backports has an easier time
doing an A/B comparison to assess whether or not they need the fix.
Especially if there's any chance that person is you circa 2024. ;)

--D

> 
> --
> Thanks,
> Ruan.
> 
> > 
> > Thanks.
> > 
> > 

  reply	other threads:[~2023-03-23 15:00 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-22 11:11 [PATCH] fsdax: unshare: zero destination if srcmap is HOLE or UNWRITTEN Shiyang Ruan
2023-03-22 23:03 ` Andrew Morton
2023-03-23  6:50   ` Shiyang Ruan
2023-03-23 14:59     ` Darrick J. Wong [this message]
2023-03-23 22:11     ` Andrew Morton
2023-03-24  1:50       ` Shiyang Ruan
2023-03-24  3:33         ` Matthew Wilcox
2023-03-24  3:42           ` Shiyang Ruan
2023-03-24  4:17             ` Matthew Wilcox
2023-03-24  4:28               ` Shiyang Ruan
2023-03-24 20:44                 ` Andrew Morton

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