bug#53541: backtrace during fresh Guix System install after during formatting

[Leo Famulari]

On Tue, Jan 25, 2022 at 09:21:00PM -0600, bdju via Bug reports for GNU Guix 
wrote:
> Using a "latest" installer image from the last day or two
> Picture of error taken with my phone attached (eh, what can ya do?)
> 
> >Device /dev/sdc is still in use.
> 
> This sticks out and appears in a couple spots.

We made many changes to the installer code today:

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$ git log --oneline 
0d37a5df7e709cadca97cfbbf9c680dfe54b8302^..4943ac86e4f95a2e14fd209f3fdaac74a0d9ca2e
4943ac86e4 installer: Use system-wide guix for system init.
ad55ccf9b1 installer: Make dump archive creation optional and selective.
112ef30b84 installer: Turn passwords into opaque records.
41eb0f01fc installer: Use dynamic-wind to setup installer.
7cbd95a9f6 installer: Add error page when running external commands.
726d0bd2f3 installer: Use named prompt to abort or break installer steps.
59fec4a1a2 installer: Add nano to PATH.
ed6567abbf installer: Replace run-command by invoke in newt/page.scm.
dad9a1c0b2 installer: Fix run-file-textbox-page when edit-button is #f.
0a74509a69 installer: Raise condition when mklabel fails.
af59e53631 installer: Use run-command-in-installer in (gnu installer parted).
408427a36c installer: Add installer-specific run command process.
0b9fbbb4dd installer: Capture external commands output.
c57ec6ed1e installer: Remove specific logging code.
2f7f1d11e9 installer: Keep PATH inside the install container.
438bf9b840 installer: Un-export syslog syntax.
4f2fd33b4f installer: Use new installer-log-line everywhere.
7251b15d30 installer: Generalize logging facility.
4a68a00c8b installer: Use define instead of let at top-level.
0d37a5df7e installer: Add crash dump upload support.
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Your report doesn't explain how to reproduce the bug. Can you test the
latest installer again and see if the bug still exists?

Here is the installer image that contains these changes:
https://ci.guix.gnu.org/build/460051/details

Or get it from here:
https://guix.gnu.org/en/download/latest/