[arch-general] Upgrade finish in a "Kernel Panic - not syncing : no init found"

[Dany De Bontridder]

Hi,

On Tue, Mar 26, 2013 at 4:14 PM, Thomas Bächler <thomas at archlinux.org> wrote:
> Am 22.03.2013 23:00, schrieb Dany De Bontridder:
>> Today,  everything works fine and I decide to keep my PC up-to-date,
>> so I run pacman -Syu and I get a message when trying to boot
>>
>>  *** Kernel Panic - not syncing : No init found. ***
>
> That is actually an impossible error message. It is only printed when
>  1) no initramfs or an invalid initramfs is attached
>  2) the kernel manages to mount the root partition
>  3) no init binary is found
Hi,


That's the weird part : I rebuilt a initramfs (mkinitcpio) (several
times), rebuild the grub.cfg and compare with the previous one...

After reinstalling I take a list of the packages (pacman -Qe) and
compare with the list before the update, the 2 lists were the same.

Maybe the initramfs was not properly built

> If a valid initramfs (containing a valid executable /init) is attached,
> then the kernel will execute that an *never* try to mount the root
> partition and find /init on its own. Thus, it will not print that message.
> Now let's assume that you didn't attach a valid initramfs. Since the
> Arch kernel contains no hard drive support and no filesystem support
> whatsoever, it is impossible for it to mount a file system and the panic
> message will *always* be
>  "unable to mount root filesystem on [...]"
>
> If you did attach a valid initramfs (as Arch does by default), then the
> error messages would be different and you would always get an emergency
> shell if something goes wrong. Even if you ignore everything and exit
> all emergency shells that pop up, you will get a different panic message:
>  "attempting to kill init"
>
> In conclusion, it is entirely impossible that you get the error message
> you quoted if you use the Arch kernel.


It *did* happen. I'm not a kernel hacker and I wasn't able to fix the
problem but I can read a message.



Kind Regards,

D.