Re: drm-kmod kernel crash fatal trap 12

On 6/15/21 11:22 AM, Bakul Shah wrote:
> On Jun 15, 2021, at 9:03 AM, John Baldwin <jhb@FreeBSD.org> wrote:
>>
>> On 6/10/21 8:13 AM, Bakul Shah wrote:
>>> On Jun 10, 2021, at 7:13 AM, Thomas Laus <lausts@acm.org> wrote:
>>>> The drm-kmod module is the latest from the pkg server.  It all
>>>> worked this past Monday after the recent drm-kmod update.
>>> This is what I did:
>>> git clone https://github.com/freebsd/drm-kmod
>>> ln -s $PWD/drm-kmod /usr/local/sys/modules
>>> Now it gets compiled every time you do make buildkernel.
>>> If things break you can do a git pull in the drm-kmod dir
>>> and rebuild.
>>
>> This is what I do now as well.  I think this is probably the
>> sanest approach to use on HEAD at least.
> 
> IIRC I learned this from one of your posts.
> 
> The PORTS_MODULES approach results in installing kernel modules
> /boot/modules, which doesn't track /boot/kernel*/.

Yes, PORTS_MODULES is not so great when you are building test kernels
from branches that are different points in time and then go back to
booting your "stock" kernel as the module is now built against the
wrong ABI and breaks your "stock" kernel.

This is why I added LOCAL_MODULES and the SRC knob to drm-kmod,
but the source knob is a bit bumpy in practice as you sometimes
need newer source than your current package.  (For example, if your
"stock" kernel only changes every few months, but you pull newer
work trees for test kernels.)  For that case, it has proven simpler
to just do the direct checkout that I can git pull when needed.

-- 
John Baldwin