New Linux kernel is crashing instantly

[Jeffrey@CollinsRTX]

I am trying to upgrade my buildroot from an old (2013.11) version to a newer (2019.02.11) version. The kernel I'm building is 3.10.6 and I retained the kernel patches for my hardware and the kernel config file from the old buildroot environment. Most of the other packages, including busybox and uClibc, also upgraded. As best as I could, since things changed over the years, I transferred the buildroot, busybox, and uClibc config stuff from the old buildroot. The build completes, but the kernel I get will not run. When I start, it immediately dies and goes to "guru meditation" mode. I tried switching my toolchain to glibc, just to see if that would help. When I got that to build, the kernel did the same thing, so I switched it all back to uClibc.

I am definitely not a kernel "guru." I have attached the VBox.log. Can anyone help me decipher what's going on?

-jeffrey

[scottgus1]

VirtualBox VM 5.1.14 r112924 win.amd64 (Jan 16 2017 16:36:58) release log
00:00:01.044310 OS Product: Windows 7
....
00:00:01.456043 VMSVGA3dEnabled <integer> = 0x0000000000000000 (0)
00:00:01.456044 VMSVGAEnabled <integer> = 0x0000000000000001 (1)

You're using an old version of Virtualbox on an older host OS, which according to the "if it aint broke" paradigm is not bad. However, you're using a VM that was apparently made in or after 6.0.x which is using the new VboxSVGA video adapter. (The above "VMSVGA" lines show up when VboxSVGA is used, further VMSVGA lines appear when VMSVGA is really being used.)

The VboxSVGA adapter did not exist in pre 6.0.x days, so the VM doesn't know what to do with this spec. Virtualbox could be programmed to just drop back and punt with the old-school VboxVGA (no S) or it might go "Huh? I give up".

Further, this log shows a boot from a CD-ROM, then the guru meditates 4 seconds later:

00:00:19.584004 VMMDev: Guest Log: BIOS: Booting from CD-ROM...
00:00:23.351965 VMMDev: Guest Log: BIOS: KBD: unsupported int 16h function 03
00:00:23.352348 VMMDev: Guest Log: BIOS: AX=0305 BX=0000 CX=0000 DX=0000
00:00:23.484103 Changing the VM state from 'RUNNING' to 'GURU_MEDITATION'

If all the upgrading stuff you were doing was on the VM's hard drive, then that activity did not influence the problem in this VM log. If you did all the upgrading and put it into the "install CD", then maybe something is broken or maybe the video problem above is causing the error.

If you change the video card to VboxVGA (no S) and still have the trouble, you may have a glitch in the upgrade. Try a regular fresh ISO from the Linux distro you're upgrading, see if Virtualbox can run the un-upgraded distro.

[Jeffrey@CollinsRTX]

Thanks for the suggestions.

As part of my debugging, I had "upgraded" to a new VirtualBox. That was a complete disaster and my development environment VM broke, so I reverted back to the old VirtualBox. That's how my boottest VM got corrupted with the VGA stuff. This kernel had died before that bad stuff was in there. Unfortunately, it's not the cause of the instant crash.

I am booting from a CD. This is not a distro. I am building a plain 3.10.6 kernel with buildroot, not getting it from anyone. The SBC vendor provides a patch that is applied before the kernel builds. It's the exact same patch as used with my older buildroot, where everything works fine. Once I get a kernel and root filesystem, I create a bootable ISO with them. Same way I do it with the older buildroot.

I ran this again with a different VM that was not corrupted by newer VirtualBox. I have attached that log. Would you mind taking a look at it?

[fth0]

First of all, I'm wondering if you chose a suitable General > Basic > Version for your guest OS: Ubuntu (64-bit) with 512 MB RAM?

Some further tidbits from both VBox.log files: Approximately 115 MB were read from the ISO image, and only 1442 assembly instructions were executed. The vCPU 0 was running in 64-bit mode when it reached an illegal assembly instruction, while vCPU 1 was still held on reset.

[Jeffrey@CollinsRTX]

The same kernel with the same kernel config file, built in an older version of buildroot, boots and runs on that same virtual machine, so it doesn't seem like the VM configuration is wrong.

[fth0]

FWIW, VirtualBox contains a debugger, documented in 12.1.4. The Built-In VM Debugger. Other than that, you could use logging or debugging possibilities that your self-built Linux kernel brings with it. Pretend that you're booting a PC with your ISO file.