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To: Vyacheslav Yurkov References: Content-Language: en-US From: Michael Opdenacker In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Date: Thu, 26 Mar 2026 09:56:21 +0000 (UTC) X-CM-Analysis: v=2.4 cv=ALriHGRn c=1 sm=1 tr=0 ts=69c502c5 a=dCRv1xv6W43JwEVryS0S5A==:617 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=d70CFdQeAAAA:8 a=AHIHXcdB7rjkH5Lyv8wA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=NcxpMcIZDGm-g932nG_k:22 X-CM-Envelope: MS4xfAUa3W2ed0K6obKBQsc//mzy/h0+0WwVJ0sQi0Pvq+N6q6lUQBpUGlnMM3nBpZCMRtVifV2RoTXTID/1v5UgIc9Ehbk/t0rtHDLNy2FShJrul292aeLz PZvBm0zT9i88zboMUAv97xvsCA4fzbf4yKwW4a6bC4ECvehMZtTkIjkk6B6pWBgjGgebeQ+G5Fp/zWV8l6KgHaZqZq0RSBd136dV3sSSqE4A2638k2aKiNIy /sP6cFX4Z2x4vD59Ah/6WAYo2rA8n/fNAUT3C0fh9ozSuQmyTrs2VsA1mREZ9UoB9y9kdxukeOzIV/UJ0NOEF9Ne/Pjd8x/RlQ8zepMvG60GJ5xZ5hXAnAGh q98DPx7zxZB2iJxed1PxK5UPo4aneF7s9Y8UvzER8F/pTJ9e9hI= X-AuthUser: michael.opdenacker@rootcommit.com Content-Transfer-Encoding: quoted-printable List-Id: X-Webhook-Received: from 45-33-107-173.ip.linodeusercontent.com [45.33.107.173] by aws-us-west-2-korg-lkml-1.web.codeaurora.org with HTTPS for ; Thu, 26 Mar 2026 09:56:30 -0000 X-Groupsio-URL: https://lists.yoctoproject.org/g/yocto/message/66355 Greetings, On 3/25/26 10:20 PM, Michael Opdenacker wrote: > Hi Slava and community, > > Do you know if overlayfs and in particular our overlayfs-etc class=20 > works when /etc is on a dm-verity root filesystem? > > Without dm-verity (regular ext4 or erofs root filesystem), everything=20 > looks all right: > # mount | grep overlay > /data/overlay-etc/upper on /etc type overlay=20 > (rw,relatime,lowerdir=3D/etc,upperdir=3D/data/overlay-etc/upper,workdir= =3D/data/overlay-etc/work,uuid=3Don) > > When /etc is on /dev/mapper/rootfs (dm-verity), everything seems=20 > messed up: > # mount | grep overlay > overlay on /var/cache type overlay=20 > (rw,relatime,lowerdir=3D/var/cache,upperdir=3D/var/volatile/cache,workd= ir=3D/var/volatile/.cache-work,uuid=3Don) > overlay on /var/lib type overlay=20 > (rw,relatime,lowerdir=3D/var/lib,upperdir=3D/var/volatile/lib,workdir=3D= /var/volatile/.lib-work,uuid=3Don) > overlay on /var/spool type overlay=20 > (rw,relatime,lowerdir=3D/var/spool,upperdir=3D/var/volatile/spool,workd= ir=3D/var/volatile/.spool-work,uuid=3Don) > overlay on /srv type overlay=20 > (rw,relatime,lowerdir=3D/srv,upperdir=3D/var/volatile/srv,workdir=3D/va= r/volatile/.srv-work,uuid=3Don) > > Systemd may be messing up, as only in this case, it does: > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Starting Bind mount volatile /var/cac= he... > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Starting Bind mount volatile /var/lib= ... > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Starting Bind mount volatile /var/spo= ol... > =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0Starting Bind mount volatile /srv... > > But these bind mounts show up as overlay mounts! > > Has anyone already encountered such an issue? I eventually managed to get /etc mounted as an overlay. It seems that=20 /sbin/init was started instead of /sbin/preinit as specified in the=20 kernel command line. I hardcoded the call to /sbin/preinit by customizing=20 openembedded-core/meta/recipes-core/initrdscripts/initramfs-framework/fin= ish=20 (in a bbappend file, of course). The code looks right though, I need to understand why this happens. Another weirdness that remains is these volatile mounts for /var/cache/,=20 /var/lib, /var/spool and /srv, which I didn't have with a regular=20 read-only root filesystem. I'll keep you posted. Cheers Michael. --=20 Root Commit Embedded Linux Training and Consulting https://rootcommit.com