Re: Kernel panic during drm/nouveau init 5.3.0-rc7-next-20190903

[Alexander Kapshuk]

On Mon, Sep 23, 2019 at 9:38 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
>
> > > 'Git bisect' has identified the following commits as being 'bad'.
> > >
> > > b96f3e7c8069b749a40ca3a33c97835d57dd45d2 is the first bad commit
> > > commit b96f3e7c8069b749a40ca3a33c97835d57dd45d2
> > > Author: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > > Date:   Mon Aug 5 16:01:10 2019 +0200
> > >
> > >     drm/ttm: use gem vma_node
> > >
> > >     Drop vma_node from ttm_buffer_object, use the gem struct
> > >     (base.vma_node) instead.
> > >
> > >     Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > >     Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>
> > >     Link: http://patchwork.freedesktop.org/patch/msgid/20190805140119.7337-9-kraxel@xxxxxxxxxx
>
> > > Today, I upgraded the kernel to 5.3.0-next-20190919, which booted fine
> > > with no Xorg regressions to report.
> > >
> > > Just wondering if the earlier kernels would not boot for me because of
> > > the changes introduced by the 'bad' commits being perhaps incomplete?
>
> Yes, we had a regression in nouveau, fixed by this patch (in drm-misc-next):
>
> commit 019cbd4a4feb3aa3a917d78e7110e3011bbff6d5
> Author: Thierry Reding <treding@xxxxxxxxxx>
> Date:   Wed Aug 14 11:00:48 2019 +0200
>
>     drm/nouveau: Initialize GEM object before TTM object
>
>     TTM assumes that drivers initialize the embedded GEM object before
>     calling the ttm_bo_init() function. This is not currently the case
>     in the Nouveau driver. Fix this by splitting up nouveau_bo_new()
>     into nouveau_bo_alloc() and nouveau_bo_init() so that the GEM can
>     be initialized before TTM BO initialization when necessary.
>
>     Fixes: b96f3e7c8069 ("drm/ttm: use gem vma_node")
>     Acked-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
>     Acked-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
>     Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
>     Link: https://patchwork.freedesktop.org/patch/msgid/20190814093524.GA31345@ulmo
>
> HTH,
>   Gerd
>

Terrific.
Thanks for the info.