Received-SPF: pass (google.com: domain of linux-ext4-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Sat, 08 May 2021 13:54:39 -0400
From:   "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Subject: regression: data corruption with ext4 on LUKS on nvme with torvalds
 master
To:     linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org,
        dm-crypt@saout.de, linux-nvme@lists.infradead.org,
        linux-block@vger.kernel.org
MIME-Version: 1.0
Message-Id: <1620493841.bxdq8r5haw.none@localhost>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
References: <1620493841.bxdq8r5haw.none.ref@localhost>
Content-Length: 1216
Precedence: bulk

Hi all,

Using torvalds master, I recently encountered data corruption on my ext4=20
volume on LUKS on NVMe. Specifically, during heavy writes, the system=20
partially hangs; SysRq-W shows that processes are blocked in the kernel=20
on I/O. After forcibly rebooting, chunks of files are replaced with=20
other, unrelated data. I'm not sure exactly what the data is; some of it=20
is unknown binary data, but in at least one case, a list of file paths=20
was inserted into a file, indicating that the data is misdirected after=20
encryption.

This issue appears to affect files receiving writes in the temporal=20
vicinity of the hang, but affects both new and old data: for example, my=20
shell history file was corrupted up to many months before.

The drive reports no SMART issues.

I believe this is a regression in the kernel related to something merged=20
in the last few days, as it consistently occurs with my most recent=20
kernel versions, but disappears when reverting to an older kernel.

I haven't investigated further, such as by bisecting. I hope this is=20
sufficient information to give someone a lead on the issue, and if it is=20
a bug, nail it down before anybody else loses data.

Regards,
Alex.