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

[Daniel Stone]

Hi Inki,

On 4 January 2016 at 12:57, Inki Dae <inki.dae at samsung.com> wrote:
> 2015년 12월 24일 22:32에 Daniel Stone 이(가) 쓴 글:
>> On 24 December 2015 at 09:10, Inki Dae <inki.dae at samsung.com> wrote:
>>> +void exynos_drm_crtc_cancel_page_flip(struct drm_crtc *crtc)
>>> +{
>>> +       struct exynos_drm_crtc *exynos_crtc = to_exynos_crtc(crtc);
>>> +       unsigned long flags;
>>> +
>>> +       spin_lock_irqsave(&crtc->dev->event_lock, flags);
>>> +       exynos_crtc->event = NULL;
>>> +       spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
>>> +}
>>
>> This will leak the event and event space; you should call
>> event->base.destroy() here. With that fixed:
>
> Right. we don't use exynos specific page flip function anymore which managed the event as a list so that the event objects can be freed by postclose callback.
> Anyway, would it be better for event->base.destory() to be called between spin lock/unlock?

You must increment event->base.file_priv->event_space (see
drm_atomic.c:destroy_vblank_event), as well as calling
event->base.destroy (see drm_fops.c:drm_read) underneath event_lock,
yes.

Cheers,
Daniel