Comment 24 for bug 1780466

That all those kernels are working now was a bit suspicious to me. I did upgrade yesterday my system which also involved an issue: The vboxdrv (VirtualBox) kernel module couldn't be loaded anymore because of a format error or such. Since a downgrade from version 5.2.14 to version 5.2.12 of VirtualBox did not solve the issue and it looked like that the upgrade also made GCC 8 a default my guess was that the compilation of the vboxdrv kernel module with GCC 8 caused this incompatibility either due to a GCC bug or my kernel being too old. I also noticed that my boot time was some seconds faster due to vboxdrv not being loaded at boot.

To make sure this issue is not related to the kernel panic at boot I tested the mainline kernel 4.18 RC5 again but it didn't panic now on boot. On testing then linux-image-4.17.0-5-generic from the Ubuntu repository it did also boot without a kernel panic and after 8 months of being haunted by kernel panics at boot I have finally an up-to-date working kernel again (also vboxdrv is being loaded successfully and VirtualBox works).

My guess is that kernel versions after linux-image-4.13.0-15-generic with virtualbox-dkms being installed and its vboxdrv compiled via GCC 7.3.0 caused this issue. I'm not sure which of the 3 candidates is to blame here but the combination of linux-image-4.17.0-5-generic with virtualbox-dkms with its vboxdrv compiled via GCC 8.1.0 works fine so it appears there is no remaining issue (at least for cosmic except somebody compiles vboxdrv with GCC 7 as I guess the kernel does panic then again).