Kernel Panic on Braswell

Troubleshooting
1

Hello,
I am experiencing rather frequent crashes on my braswell machine. It says

[drm:valleyview_update_wm [i915]] *ERROR* timed out waiting for Punit DDR DVFS request

I am on Rockstor 3.8-9 using Kernel 4.2.2 and googling around a bit, I found that there seems to be a bug in the intel graphics driver (also indicated by the message). Information is relatively sparse, but this seems to be fixed, though it’s not clear to me how to get a fixed version. Any ideas? This is a rather annoying bug, because it renders my server practically unusable. Any workarounds welcome…

2

Did you try enabling DDR DVFS support in the BIOS? I have no idea what it is, but the patch seems to suggest that the bug is triggered if it’s disabled in the BIOS. If you can enable it, the bug may not be triggered?

If you are on the testing channel, then you could try 4.2.5 kernel, which is the default. May be the patch went into it, just a wild guess.

3

Uh Oh, I had a big screw-up doing that. I noticed that the newest kernel was already installed, but for some reason grub didn’t start the first boot entry, so it ended up booting the older version. looking at the grub commands, I figured one could change that by invoking “grub2-set-default 1”, but that apparently just deleted my grub.cfg.
Anyways, I had to create a new one by installing rocksor on a virtualmachine and copying the grub.cfg from there, since I couldn’t get it to run just from the grub-console. Maybe it would help to post the grub2 commands necessary to start rockstor somewhere. It’s not really trivial with that setup.

While restarting, I noticed that the above error message does not seem to be the issue at hand. It shows up at every start. I’ll have to wait for my next crash (it’s coming for sure) to get the actual reason…

4

Upon every boot, Rockstor will reset the default kernel to what it should be. So, simply rebooting should take you to the right kernel.

5

New Kernel, old issue. But as I said, the above Error message comes up everytime, and there’s no setting whatsoever in the bios for DVFS support.

Looks like a btrfs issue:

DSC05388.JPG1500×1000 625 KB

And just a moment ago ago I saw another panic, this time saying
kernel bug at fs/btrfs/extent-tree.c:1833

Is there a way to copy the log?

6

Can I disable that behavior as I’m running a non standard kernel (Actually i have 4.3 final compiling now) and it’s annoying if I forget about that and reboot into the stock kernel. Tried saving a different default with the grub command line tools but looks like rockstor overwrites it again :frowning:

@arneko the 4.3-rc7 RPM i built is found at http://scrat.dragon2611.net/rockstor/RPMS/x86_64/ no guarantees given but if you want to try it you are more then welcome.

I’ll upload the files for 4.3 once it’s compiled and I’ve checked to see if it boots on my machine.

Alternatively you can grab the source from kernel.org and build your own or I guess now 4.3 is final there will be an elrepo package for it soon.

7

@Dragon2611 Thanks, I might try that. Actually, I half expected the 4.3 kernel to already be in the elrepo repo already?! DIdn’t try it yet, because I don’t have permanent physical access to that machine. Which makes all this even more annoying.

Testing different (older stock-) kernels, I noticed that rockstor does a check on the kernel it’s running. interesting. That check is probably also responsible for your changing grub-configuration.

I am considering other points of failures as well, that I want to check next time I have access:

  1. faulty RAM - Will do a memory check
  2. Maybe having rockstor on a USB-thumbdrive is related (how would I check for errors regarding that)
  3. Well - newest kernel
8

The 4.3 kernel RPM built successfully and I’ve uploaded it (Actually I uploaded it earlier but forgot to post)

It hasn’t exploded my installation yet but no guarantees given.