Bug#958397: Missing 60-block.rules breaks grub-installer

Steve McIntyre steve at einval.com
Tue Apr 21 15:34:45 BST 2020

Hey Pascal,

Awesome work on tracking this down!

On Tue, Apr 21, 2020 at 03:19:36PM +0200, Pascal Hambourg wrote:
>Package: udev-udeb
>Version: 241-7~deb10u3
>Control: found -1 232-25+deb9u12
>Control: unarchive 852323
>X-Debbugs-CC: steve at einval.com
>Udev has a rule with OPTIONS+="watch" to generate an event and update
>symlinks in /dev/disk/ when a block device is written to. In Jessie, the rule
>was in /lib/udev/rules.d/60-persistent-storage.rules. In Stretch and Buster,
>it was moved to /lib/udev/rules.d/60-block.rules. However
>/lib/udev/rules.d/60-block.rules was *not* included in :
>- the initramfs hook script /usr/share/initramfs-tools/hooks/udev, therefore
>in the initramfs built by update-initramfs
>- the udev-udeb package
>- the Debian installer initrd.gz (I guess it uses udev-udeb)
>The most visible consequence is in the Debian installer. When a device is
>formatted, symbolic links pointing to that device in /dev/disk/ are not
>updated immediately. Then if the symlink pointing to the root device in
>/dev/disk/by-uuid/ is missing or wrong, update-grub/grub-mkconfig puts the
>root device name instead of the UUID in the root= kernel parameter (see
>/etc/grub.d/10_linux). Drive and partition device names are unreliable and
>may change at each boot, causing the boot to fail.
>The following bugs may be related to this issue :
>Steps to reproduce the issue :
>Boot the Debian installer.
>Select "advanced options" > "Expert install".
>Follow steps up to "Partition disks".
>Select manual partitioning.
>Create or select and format a partition for /.
>Do not create or use any swaps.
>Install the base system.
>Skip "Configure the package manager" and "Select and install software".
>Install the GRUB boot loader.
>Jump into a shell.
>Check the symlink pointing to the root partition in /dev/disk/by-uuid/ is
>missing or wrong.
>Check that /target/boot/grub/grub.cfg "linux" lines have
>root=/dev/<partition> instead of root=UUID=<uuid>.
>Suggested fix :
>The issue could be worked around by executing "udevadm trigger" to update
>symlinks at a proper time after formatting the root filesystem and before
>installing GRUB. This is actually what seems to happen at the "select and
>install software" step. But I think is is easier, safer and cleaner to
>include /lib/udev/rules.d/60-block.rules and fix the root cause than to rely
>on executing "udevadm trigger" at the proper time.

To be honest, I'm curious if there's a good reason to not just include
all the udeb rules files in the udev-udeb package? That would fix this
bug and save us from any potential future possible reshuffles. It's
not like they're very large.

Happy to send a patch to modify debian/udev-udeb.install if that will
help. It would be lovely to also get the same fix backported to Buster
(and even Stretch!) if you're ok with that.

/me goes to do a test build now.

Steve McIntyre, Cambridge, UK.                                steve at einval.com
You lock the door
And throw away the key
There's someone in my head but it's not me 

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