Warning about debug kernel in dmesg -T output

[Kai Kratz]

Due to an unrelated issue I was looking tin dmesg -T and saw this very prominent notice:

I did NOT install any debug kernel and I am running the latest kernel from the official Ubuntu 18.04 repo.

[Fr Aug 10 14:01:25 2018] **********************************************************
[Fr Aug 10 14:01:25 2018] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
[Fr Aug 10 14:01:25 2018] ** **
[Fr Aug 10 14:01:25 2018] ** trace_printk() being used. Allocating extra memory. **
[Fr Aug 10 14:01:25 2018] ** **
[Fr Aug 10 14:01:25 2018] ** This means that this is a DEBUG kernel and it is **
[Fr Aug 10 14:01:25 2018] ** unsafe for production use. **
[Fr Aug 10 14:01:25 2018] ** **
[Fr Aug 10 14:01:25 2018] ** If you see this message and you are not debugging **
[Fr Aug 10 14:01:25 2018] ** the kernel, report this immediately to your vendor! **
[Fr Aug 10 14:01:25 2018] ** **
[Fr Aug 10 14:01:25 2018] ** NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE **
[Fr Aug 10 14:01:25 2018] **********************************************************

System info:
~ » lsb_release -a kkratz@kkratz
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

apt list | grep linux-image
...
linux-image-4.15.0-30-generic/bionic-updates,bionic-security,now 4.15.0-30.32 amd64 [installed,automatic]
...

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Bram Stolk (b-stolk)]

This is still an issue in 2019.

From the latest kernel in LTS: linux-image-4.15.0-66-generic

[Bram Stolk (b-stolk)]

Mine was a false alarm. The printk() did not come from the kernel itself, but from a proprietary kernel module.

After removing Intel VTune from the system, the notice disappeared.