Kernel panic on VF50 after power failing

Technical Support
, , , ,
1

My Colibri VF50 module cannot boot properly after power failing. It stops booting with such information:

Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
I’ve already got this error two times after power failing.
Is this true that fs crashing after loosening power? How can I prevent fs crashing in such cases (ups is not possible to use)?

2

Can you please provide complete boot logs if possible ?

3

Which image are you using? Is this the Console only image? Could it be that the file system was full (or almost full) at that point?

4

I’ll try to repeat this error (I’ve already reinstalled Linux on module) and show that logs.

5

I use Colibri_VF_LinuxImageV2.6.1Beta1_20161001 which is not Console only image.
It takes near 100 Mb from 128 Mb

6

I’ve just got this error again. See logs in attachment: Boot logs

7

Thanks for the log.

We had seen issues before in the lower layered UBI and it also involved U-Boot and/or Fastmap, but this seems unlikely to be the issue here.

The message mentions an UBIFS error, it seems that a node got corrupted. UBIFS should be safe against power failures so this should really not happen.

It could be related to a file system full/almost full corner case issue. It is really hard for a file system to operate when it is about to be full, especially if it is a compressing file system like UBIFS. I recommend to strip down the image a bit, and/or disable logging so that there is always some space left.

I see that you are using a custom kernel, what changes, if any, do you made to the kernel?

8

Note that you don’t have 128MB NAND available for the root file system: There is overhead for the bad block management (~2MB), the Boot Loader, Kernel and Device Tree (~10MB) plus UBI wear leveling/volume managment and UBIFS file system overhead. With the LXDE image the NAND is pretty much full…

9

Did you flash the latest image from scratch ? If it is not flashed from scratch ateast make sure to erase the nand chip before flashing the latest image as mentioned in the article here. We are doing a powercut stress test on Colibri VF50 with our prebuild Linux Image, the test is running since 10-15-2016, so far no issues observed.