"Mounted root does not match boot loader environment" error with overlayroot setup

General Discussions
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1

When using the overlayroot package on Debian to mount a rw overlay on top of a ro rootfs, the rootfs update module fails with the following error:

"Mounted root does not match boot loader environment ($1)!"

See this line: mender/support/modules/rootfs-image at 9fc5b2fec4b525ee045cc93c0a030d94aa308394 · mendersoftware/mender · GitHub

Is this a bug? Does mender actually care about how the root is mounted after handing it over to the kernel / initramfs?

Can this check be disabled? Or can it be changed to instead check that the passive partition is not mounted?

Thanks!

2

Another option to check wether the active partition is the correct one could be to check what was passed to kernel via /proc/cmdline. Something like:

ROOT_DEVICE=$(findfs $(grep -o '\(^\| \)root=[^ ]*' /proc/cmdline | cut -d= -f2-))
3

Put up a PR for the /proc/cmdline approach:

I assume the delta update module would need a similar fix?

4

Hi @adbjo,

Thanks so much for the detailed analysis and follow up contribution. I’ve answered there, as I think the code is the main relevant thing here and we should focus on that.

Concerning the delta update module, I think a similar patch might be useful, but can’t judge this right now. Deltas being a Pro+ feature, I would encourage to file this through support@mender.io to get started, I’ll keep an eye open for it there and eventually poke the relevant folks then.

Greetz,
Josef