Why does 'update-grub' detect kernels twice?

Question

When updating my GRUB config files (e.g. automatically after kernel updates), I get an output mentioning all Linux kernels (both the vmlinuz and initrd file) twice:

$ sudo update-grub
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.2.0-19-generic
Found initrd image: /boot/initrd.img-4.2.0-19-generic
Found Windows 7 (loader) on /dev/sda1
Found linux image: /boot/vmlinuz-4.2.0-19-generic
Found initrd image: /boot/initrd.img-4.2.0-19-generic
Found memtest86+ image: /memtest86+.elf
Found memtest86+ image: /memtest86+.bin
done

The GRUB boot menu does not show any duplicate entries though.

After reading grub shows same linux image twice (which is from 2011/01/01!), I checked my list of executable scripts in /etc/grub.d:

-rwxr-xr-x   1 root root  9791 Okt 14 18:36 00_header*
-rwxr-xr-x   1 root root  6058 Sep  4 13:13 05_debian_theme*
-rwxr-xr-x   1 root root   618 Okt 30 12:59 10_linux_proxy*
-rwxr-xr-x   1 root root   229 Okt 30 12:59 30_os-prober_proxy*
-rwxr-xr-x   1 root root   621 Okt 30 12:59 33_linux_proxy*
-rwxr-xr-x   1 root root 11082 Okt 14 18:36 34_linux_xen*
-rwxr-xr-x   1 root root   294 Okt 30 12:59 35_memtest86+_proxy*
-rwxr-xr-x   1 root root  1418 Okt 14 18:36 36_uefi-firmware*
-rwxr-xr-x   1 root root   322 Okt 30 12:59 40_custom_proxy*
-rwxr-xr-x   1 root root   216 Okt 14 18:36 41_custom*

As the answer in the linked question shows only a short list of 6 scripts, which are mostly named differently, I assume that it is either outdated or that I am just a special case...

However, I could not spot two identical files, as 10_linux_proxy and 33_linux_proxy have similar names, but different file sizes.

Now, why do I get duplicate messages for all Linux kernels in the update-grub output and how do I fix it?
Do I need to delete one of the *_linux_proxy files? If yes, which one?
And what could have initially caused this problem?

UPDATE:

I have just disabled the execution permission of 33_linux_proxy and ran update-grub. It looked correct, as there was only one occurrence of each kernel version and file in the output. So I rebooted, but there was no Ubuntu entry at all any more!
I managed to reset the configuration and am now back in the same situation as before.

Should I try disabling the other one (10_linux_proxy) now? I am not really looking forward to restore the old configuration through a live session again if it fails...

score 1 · Answer 1 · answered Dec 03 '15 at 19:48

1

I have encountered this problem before, and the extra kernels didn't show up in the GRUB boot menu if I remember, but it was a while back.

You might try deleting one of the *_linux_proxy files, and back it up first of course. That should get rid of detection, as you suspected. I would remove the second one, but they should be identical.

answered Dec 03 '15 at 19:48

Daniel Smith - Chatbot

116

Can you say anything about possible reasons why this seems to happen very often? Where could this second file come from? And might you know a link to any official description which files the /etc/grub.d directory should contain and what the proxy stuff means? – Byte Commander Dec 03 '15 at 19:56
I haven't yet been programed with the answer to that question – Daniel Smith - Chatbot Dec 03 '15 at 19:57
But on a serious note, I seriously don't know. – Daniel Smith - Chatbot Dec 03 '15 at 19:57
I just disabled the execution permission of the second one (33_linux_proxy), ran sudo update-grub, which displayed the Linux kernels only once, but on reboot, I was left with a GRUB menu without any Linux entry! Had to restore the configuration from a live session. So why does that not work? – Byte Commander Dec 10 '15 at 09:13
I have no idea... – Daniel Smith - Chatbot Feb 11 '16 at 00:20

Why does 'update-grub' detect kernels twice?

UPDATE:

1 Answers1