Kernel panic - not syncing: VFS

t_neo · February 26, 2018, 4:04pm

Tumbleweed update went wrong and now my boot is broken. When I boot the default kernel through Grub I end up with:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,1)
https://s17.postimg.org/82ztw75j3/kernel_panic.jpg

I can get into the system by going into advanced options and select the second kernel entry there. When I select the first entry it throws the same error. To the eye the kernel entries are identical.
https://s17.postimg.org/o2ihfu1lr/grub.jpg

When I booted the system I created a snapshot and rebooted. Selecting the snapshot (or any other in read-only) is unable to boot the system and I end in maintenance mode.

I searched online and found the suse help page (https://www.suse.com/support/kb/doc/?id=3864925) that suggested to run *mkinitrd *but that did not have a resolving effect.

By going through the 2nd option in my advanced options I was able to eventually boot my system, but it is very unresponsive and slow.

My questions are:

I haven seen anything odd in /etc/fstab. What can I do to fix the kernel panic error?
Where can I find the advanced options details, to see what the difference is?
Under my current boot, yast is not opening boot-loader details, how to check?

dcurtisfra · February 26, 2018, 5:29pm

In the openSUSE Wiki, there’s the following Support Database article:

SDB: Rescue system on disk: <https://en.opensuse.org/SDB:Rescue_system_on_disk>.

There’s also this SDB article for recovering root’s password but, it also works for other instances where a Rescue system is booted to repair the system disk to be booted:

SDB: Recover root password: <https://en.opensuse.org/SDB:Recover_root_password>.

t_neo · February 26, 2018, 5:36pm

Thanks for the suggested pages. However I don’t have issues with the root password. And the rescue system page states “Obviously, this isn’t any good for when the hard disk or the boot loader needs to be repaired…” I don’t really see how that will resolve the kernel panic and the oddity that I do can boot, but not following the default option.

dcurtisfra · February 26, 2018, 5:46pm

The “Rescue Disk” article is meant to describe how to produce a rescue disk if an installation DVD or installation USB (with an ISO image) is not at hand.
If you have an installation DVD or installation USB, you can boot it and select the Rescue System. Then, proceed as for “recovering the root password”: in other words mount the defective system disk and proceed to recover the boot loader or whatever else needs to be done.

t_neo · February 26, 2018, 8:53pm

Making progress.

I have booted the rescue system and followed the “Forgot root password” process to mount the disk and through Yast2 to install the boot-loader again. The output of the boot-loader installation threw an error, but it showed something interesting. As I now understand the difference in entries in the advanced options in GRUB. The second entry in my advanced options is now changed into kernel 4.15.4 instead of only 4.15.5. Booting that kernel all works as expected.

Upon reboot GRUB boots the kernel 4.15.5 but now I end in emergency mode.

dcurtisfra · February 27, 2018, 10:17am

Given that, something seems to have gone very wrong at the last Tumbleweed upgrade: using the 4.15.4 kernel, try to re-upgrade to the 4.15.5 kernel.
If that doesn’t help, a Bug Report is needed.

t_neo · February 28, 2018, 8:30pm

Re-Installing the new kernel 4.14.5 brought me further from home as it removed the 4.14.4 kernel and thus the advanced fallback option. Upon reboot I was presented again with the kernel panic screen. After fiddling for several hours with the issue I ended up re-installing TW which was faster than the fiddling. Too bad the rescue system process did not work, but I learned something new there.