[bug #63030] Different partition grub entries get identical root=UUID=sameuuid

[Reik Red]

URL:
  <https://savannah.gnu.org/bugs/?63030>

                 Summary: Different partition grub entries get identical
root=UUID=sameuuid
                 Project: GNU GRUB
               Submitter: reikred
               Submitted: Thu 08 Sep 2022 02:03:44 AM UTC
                Category: Configuration
                Severity: Major
                Priority: 5 - Normal
              Item Group: Software Error
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
                 Release: other
                 Release: 
         Discussion Lock: Any
         Reproducibility: None
         Planned Release: None


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Follow-up Comments:


-------------------------------------------------------
Date: Thu 08 Sep 2022 02:03:44 AM UTC By: Reik Red <reikred>
I have 3 versions of Ubuntu (20,21,22) installed on my machine, but when I
select to boot 20 or 21 it still boots 22! The reason turns out to be that ALL
the entries in grub.cfg have the same UUID specified:

linux .... root=UUID=....ddde

But the ....ddde partition is the one that contains Ubuntu 22.04. The grub
menu shows an entry as Ubuntu 21.04 (or 20.04.3), but grub still boots Ubuntu
22.04 from that entry because the wrong UUID is being used.

Running update-grub and/or grub-mkconfig is what produces the errant grub.cfg
file. And I don't understand why this is happening.

grub-mkconfig is reporting sensible findings, such as

Found Ubuntu 20.04.3 LTS (20.04) on /dev/sda3
Found Ubuntu 21.04 (21.04) on /dev/sda4

(this is of course grub2, which is called just grub for several years now)

Added: output of sudo blkid /dev/sda*. It seems normal, the UUID are all
different.

sudo blkid /dev/sda*
/dev/sda: PTUUID="5adeb302-3e17-421e-aabc-41bb2377a86f" PTTYPE="gpt"
/dev/sda1: LABEL_FATBOOT="EASY2BOOT" LABEL="EASY2BOOT" UUID="3C18-9DDC"
BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="Microsoft basic data"
PARTUUID="2d2d85db-6382-43f5-9166-1d31da742e06"
/dev/sda2: LABEL="X.SSD./root-ub22"
UUID="8d66f7b3-dc29-40b1-b0f0-06105da0ddde" BLOCK_SIZE="4096" TYPE="ext4"
PTTYPE="dos" PARTLABEL="Linux filesystem"
PARTUUID="c5a10849-2f94-4917-9e56-cc5e594da0ee"
/dev/sda3: LABEL="X.SSD./root-ub21"
UUID="d92b1ba1-ede6-4ba4-8f43-cfd7b89d4157" BLOCK_SIZE="4096" TYPE="ext4"
PTTYPE="dos" PARTLABEL="Linux filesystem"
PARTUUID="27fdc527-1e9b-4b77-a49e-dd92299b2ec7"
/dev/sda4: LABEL="X.SSD./root-ub20"
UUID="4cc88374-3255-475b-be75-59ab2c462934" BLOCK_SIZE="4096" TYPE="ext4"
PTTYPE="dos" PARTUUID="a2aeaf9e-4ecc-473e-8c8e-e82e16dc7846"
/dev/sda5: UUID="1D3E-50B4" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI system
partition" PARTUUID="4cc2c6b3-9678-4819-a18a-139ceecebb94"

This bug might be easier to debug if grub-mkconfig had a verbose mode that
would report how the UUID was determined, and/or an option to generate a menu
item for just a list of partitions, say something like

grub-mkconfig -o grub.cfg.debug /dev/sda2 /dev/sda3

Version: grub-2.06










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