Kernel 4.4.0-89 panics on boot on xenial

[Phil Pemberton]

After applying the 4.4.0-89 kernel update, I get a panic on boot.

4.4.0-87 boots normally.

I expected that 4.4.0-89 would boot normally (as 4.4.0-87) instead of crashing.

Systemd displays an announcement: "Starting udev Wait for Complete Device Initialization...", then I get:

  * "kobject: can not set name properly!"
  * "BUG: unable to handle kernel null pointer dereference at 00000000
  * A kernel error backtrace

Part of the backtrace is (I'm having to enter this from a video):

Call Trace:
  [ffffffff81258ff3] ep_alloc+0x43/0xe0
  [ffffffff81259162] SyS_epoll_create1+0x42/0xe0
  [ffffffff81841f32] entry_SYSCALL_64_fastpath+0x16/0x71

RIP [ffffffff811ed65b] kmem_cache_alloc_trace+0x7b/0x1f0

Kernel panic - not syncing: CRED: put_cred_rcu() sees ffff880231fc3cc0 with usage -1

lsb_release -rd:

Description: Ubuntu 16.04.3 LTS
Release: 16.04

[Phil Pemberton (philpem)]

I'd like to provide a better backtrace if it's needed, but I'm not sure how to do this.

Attaching lspci -vnvn

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1709511

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Phil Pemberton (philpem)]

I can't provide the Apport logs; it asks me to log in to Launchpad using Lynx, then fails with "Bad bot!"

Is there an alternative way to do this? The machine is a headless server.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream stable kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.4 stable kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.80

[Phil Pemberton (philpem)]

I just upgraded to 4.4.0-91 from the main repository, and it boots again!

All my virtual machines are running too.

Looks like this is fixed in something which was changed between -89 and -91.

[Russell Morris (6-u3untu-h)]

Interesting - as I'm having to go back to 4.4.0-89 to get my machine to boot ... kernel panic and hang on 4.4.0-91. I'm happy to take logs, just not sure how to ... :-(

[Joseph Salisbury (jsalisbury)]

@Russell Morris, you may want to open a new bug, since the original bug reporter says this one is now fixed in comment #6.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]