[PATCH v3] drm/exynos: fix kernel panic issue at drm releasing

[Daniel Vetter]

On Fri, Jan 8, 2016 at 9:46 AM, Inki Dae <inki.dae at samsung.com> wrote:
> This patch fixes a kernel panic issue which happened
> when drm driver is closed while modetest.
>
> This issue could be reproduced easily by launching modetest
> with page flip repeatedly.
>
> The reason is that invalid drm_file object could be accessed by
> send_vblank_event function when finishing page flip if the drm_file
> object was removed by drm_release and there was a pended page
> flip event which was already committed to hardware.
>
> So this patch makes the pended page flip event to be cancelled by
> preclose callback which is called at front of drm_release function.
>
> Changelog v2:
> - free vblank event objects belonging to the request process,
>   increment event space and decrease pending_update when cancelling
>   the event
>
> Changelog v3:
> - initialize only device specific things. Each page flip event object
>   is created by DRM core so DRM core should release the object including
>   incrementing event space.
>
> Signed-off-by: Inki Dae <inki.dae at samsung.com>
> Reviewed-by: Daniel Stone <daniels at collabora.com>

Note that after my drm_event cleanup series has landed (aiming for
early 4.6) you can/should revert this again. But it's too big as a
bugfix this late in 4.5. Ack/tested-by from exynos on that series
would be great.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch