Segmentation fault at address 0x0 -> possibly fixed in releases higher than 5.1.6

[vrishab]

64-bit Host: Debian unstable - virtualbox 5.1.4 ( Linux unstable 4.7.0-1-amd64 #1 SMP Debian 4.7.2-1 (2016-08-28) x86_64 )
32-bit Guest: Debian unstable - virtualbox 5.1.4 ( Linux sid-reportbug 4.7.0-1-686-pae #1 SMP Debian 4.7.2-1 (2016-08-28) i686 )

[   485.787] (EE) Backtrace:
[   485.787] (EE) 0: /usr/lib/xorg/Xorg (xorg_backtrace+0x52) [0x8027b832]
[   485.788] (EE) 1: /usr/lib/xorg/Xorg (0x800d2000+0x1adc92) [0x8027fc92]
[   485.788] (EE) 2: linux-gate.so.1 (__kernel_rt_sigreturn+0x0) [0xb76e1d4c]
[   485.788] (EE) 3: /usr/lib/xorg/modules/drivers/vboxvideo_drv.so (VBoxVideoGetVRAMSize+0x8) [0xb76d7b98]
[   485.788] (EE) 4: /usr/lib/xorg/modules/drivers/vboxvideo_drv.so (0xb76d0000+0x5f64) [0xb76d5f64]
[   485.788] (EE) 5: /usr/lib/xorg/Xorg (InitOutput+0xb14) [0x80155104]
[   485.788] (EE) 
[   485.788] (EE) Segmentation fault at address 0x0

I have few other guests ( FC24, Windows 8 ) working fine.

Attached the full Xorg.log

[vrishab]

Guest Xorg log file

[vrishab]

Tried the same with 5.1.6-110634~Debian~stretch ( + compiled 5.1.6-110634~Debian~stretch guest additions in guest ). Still X doesn't start, and keeps crashing.

Note: The guest was working fine for months. Crash started happening a few ( ~4 ) days ago. Probably due to a kernel upgrade.

[Michael Thayer]

User space vboxvideo is crashing because you are running non-root X. Normally user space vboxvideo should not be running at all on this guest, and instead user space modesetting and kernel vboxvideo should be used. I presume that for some reason the kernel vboxvideo driver did not load correctly. Could you investigate that?

[vrishab]

[root@guest]# apt-get install dkms

and the problem seem to have disappeared. Tried uninstalling dkms to see, if the problem appears again. But, no issues then too.

[Michael Thayer]

In other words your guest system was not set up to build kernel modules, and installing dkms fixed that. Probably worth seeing if I can make things fail in a more understandable way in that case.

[vrishab]

That would be great.

I thought I installed 'dkms', but somehow missed it as I was working on quite a few guest oses.

Also, a line can be printed ( on the guest additions kernel module build ouput ), to install dkms.

[Michael Thayer]

Just as information, dkms is no longer used by VirtualBox. However it helps indirectly, as installing dkms causes all the components needed to build drivers to be installed as well.

[Michael Thayer]

Please try the current Guest Additions test build<1>.

<1> https://www.virtualbox.org/wiki/Testbuilds

[vrishab]

The current guest additions in https://www.virtualbox.org/wiki/Testbuilds

is

https://www.virtualbox.org/download/testcase/VBoxGuestAdditions_5.1.5-110588.iso

Is this the latest ? I already have 5.1.6 installed.

[vrishab]

I have built virtualbox 5.1.51 r63850 from svn. It is working fine. But, I don't have a way to build / install extpack and guest additions from svn. Please let me know if there are instructions for them.

[Michael Thayer]

Sorry, updated the test build. Please try again.