Bug#798311: nvidia-kernel-dkms: fails to build against 4.2.0-trunk in experimental

[Luca Boccassi]

reassign 798311 linux 4.2-1~exp1
tags 798311 upstream wontfix
thanks

On Tue, 2015-09-08 at 08:28 +1000, Brian May wrote:
Package: nvidia-kernel-dkms
> Version: 352.30-1
> Severity: normal
> 
> falidae# dpkg -i /var/cache/apt/archives/linux-image-4.2.0-trunk-amd64_4.2-1~exp1_amd64.deb
> (Reading database ... 322134 files and directories currently installed.)
> Preparing to unpack .../linux-image-4.2.0-trunk-amd64_4.2-1~exp1_amd64.deb ...
> Unpacking linux-image-4.2.0-trunk-amd64 (4.2-1~exp1) over (4.2-1~exp1) ...
> Setting up linux-image-4.2.0-trunk-amd64 (4.2-1~exp1) ...
> /etc/kernel/postinst.d/dkms:
> Error!  Build of nvidia.ko failed for: 4.2.0-trunk-amd64 (x86_64)
> Consult the make.log in the build directory
> /var/lib/dkms/nvidia-current/352.30/build/ for more information.
> 
> Not sure what the error is, all I see is a lot of warnings. Suspect the
> error might be related to the undefined symbols:

Hello Brian,

I faced the same problem the other day when I tried the new kernel from
experimental.

The actual problem is the following line:

FATAL: modpost: GPL-incompatible module nvidia.ko uses GPL-only symbol 'flush_workqueue'

Unfortunately there is nothing we can do on the Nvidia side since it's a
problem in the kernel code itself. You'd have to patch and rebuild the
whole kernel to get past it. It's a regression in 4.2, where a symbol
was inlined and the license was mistakenly changed. A patch has already
been sent to the upstream kernel mailing list[1] to fix it, and it
should appear in the next 4.2 stable point release, hopefully soon.

See also this discussion on the Nvidia forum: [2].

Kind regards,
Luca Boccassi

[1] https://lkml.org/lkml/2015/9/3/411
[2] https://forums.geforce.com/default/topic/849487/linux-v4-2-uses-gpl-only-symbol-flush_workqueue-/