[vbox-dev] Cannot compile guest additions

[Sérgio Basto]

On Sat, 2020-12-26 at 12:11 -0700, Dan Egli wrote:
> I'm using Vbox 6.1.16 r140961 (Qt5.6.2) to host a few Gentoo Linux 
> boxes. On those boxes I have kernel 5.4.80. I tried to install the
> guest 
> additions so that I could enable copy and paste and what not, but
> the 
> compile failed. The log shows a bunch of undefined symbols:
> 
> ERROR: "ttm_bo_eviction_valuable" [/tmp/vbox.0/vboxvideo.ko]
> undefined!
> ERROR: "ttm_tt_fini" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_put" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_move_to_lru_tail" [/tmp/vbox.0/vboxvideo.ko]
> undefined!
> ERROR: "ttm_bo_validate" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_init" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_add_to_lru" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_kmap" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_tt_init" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_dma_acc_size" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_init_mm" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_device_init" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_del_sub_from_lru" [/tmp/vbox.0/vboxvideo.ko]
> undefined!
> ERROR: "ttm_bo_kunmap" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_device_release" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_manager_func" [/tmp/vbox.0/vboxvideo.ko] undefined!
> ERROR: "ttm_bo_mmap" [/tmp/vbox.0/vboxvideo.ko] undefined!

please look at  
https://www.virtualbox.org/ticket/20055

> What's causing this and is there an easy fix?
> 
-- 
Sérgio M. B.