Subject: Re: bug#53541: [installer] backtrace during fresh Guix System install after during formatting

From: Mathieu Othacehe <[email-masked]>
Date: Sat, 22 Oct 2022 19:00:39 +0200

Hey,

> I was able to reproduce it on real hardware, following those
> instructions. The dump is available here if people want to join the
> party: dump.guix.gnu.org/download/installer-dump-304492ff.

So the backtrace suggests that we are trying to open /dev/nvme0n1p1 to
read its superblock:

--8<---------------cut here---------------start------------->8---
           9 (open "/dev/nvme0n1p1" 524288 #<undefined>)
--8<---------------cut here---------------end--------------->8---

and that it fails because the file does not exist:

--8<---------------cut here---------------start------------->8---
  1780:13  6 (_ #<&compound-exception components: (#<&external-error> #<&origin origin: "open-fdes"> #<&message message: "~A"> #<&irritants irritants: ("No such file or directory")> #<&exception-w…>)
--8<---------------cut here---------------end--------------->8---

This open call originates from check-user-partitions in (gnu installer
parted). If we arrive here, it means that the file *should* exist.

Looking at the kernel trace, the two last lines are:

--8<---------------cut here---------------start------------->8---
[   72.271204]  nvme0n1: p1 p2 p3 p4
[  127.415648]  nvme0n1: p1 p2
--8<---------------cut here---------------end--------------->8---

so the disk partition table is updated because we move from 4 to 2
partitions. Could it be possible that during a brief period of time the
/dev/nvme0n1p1 file disappears then re-appears?

I'll try to reproduce it a VM to conduct more testing.

Mathieu