* [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached
@ 2023-02-02 4:57 Chen-Yu Tsai
2023-02-02 9:14 ` AngeloGioacchino Del Regno
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Chen-Yu Tsai @ 2023-02-02 4:57 UTC (permalink / raw)
To: Chun-Kuang Hu, Philipp Zabel, David Airlie, Daniel Vetter
Cc: Chen-Yu Tsai, dri-devel, linux-mediatek, linux-kernel, Guillaume Ranquet
The MediaTek DisplayPort interface bridge driver starts its interrupts
as soon as its probed. However when the interrupts trigger the bridge
might not have been attached to a DRM device. As drm_helper_hpd_irq_event()
does not check whether the passed in drm_device is valid or not, a NULL
pointer passed in results in a kernel NULL pointer dereference in it.
Check whether the bridge is attached and only trigger an HPD event if
it is.
Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>
---
Changes since v1
- Dropped prerequisite-patch-ids
- Added Guillaume's Reviewed-by
This applies on top of mediatek-drm-next.
drivers/gpu/drm/mediatek/mtk_dp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
index 1f94fcc144d3..a82f53e1a146 100644
--- a/drivers/gpu/drm/mediatek/mtk_dp.c
+++ b/drivers/gpu/drm/mediatek/mtk_dp.c
@@ -1823,7 +1823,8 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags);
if (status & MTK_DP_THREAD_CABLE_STATE_CHG) {
- drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
+ if (mtk_dp->bridge.dev)
+ drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
if (!mtk_dp->train_info.cable_plugged_in) {
mtk_dp_disable_sdp_aui(mtk_dp);
--
2.39.1.456.gfc5497dd1b-goog
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached
2023-02-02 4:57 [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached Chen-Yu Tsai
@ 2023-02-02 9:14 ` AngeloGioacchino Del Regno
2023-02-02 9:56 ` Matthias Brugger
2023-03-12 15:41 ` Chun-Kuang Hu
2 siblings, 0 replies; 4+ messages in thread
From: AngeloGioacchino Del Regno @ 2023-02-02 9:14 UTC (permalink / raw)
To: Chen-Yu Tsai, Chun-Kuang Hu, Philipp Zabel, David Airlie, Daniel Vetter
Cc: dri-devel, linux-mediatek, linux-kernel, Guillaume Ranquet
Il 02/02/23 05:57, Chen-Yu Tsai ha scritto:
> The MediaTek DisplayPort interface bridge driver starts its interrupts
> as soon as its probed. However when the interrupts trigger the bridge
> might not have been attached to a DRM device. As drm_helper_hpd_irq_event()
> does not check whether the passed in drm_device is valid or not, a NULL
> pointer passed in results in a kernel NULL pointer dereference in it.
>
> Check whether the bridge is attached and only trigger an HPD event if
> it is.
>
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached
2023-02-02 4:57 [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached Chen-Yu Tsai
2023-02-02 9:14 ` AngeloGioacchino Del Regno
@ 2023-02-02 9:56 ` Matthias Brugger
2023-03-12 15:41 ` Chun-Kuang Hu
2 siblings, 0 replies; 4+ messages in thread
From: Matthias Brugger @ 2023-02-02 9:56 UTC (permalink / raw)
To: Chen-Yu Tsai, Chun-Kuang Hu, Philipp Zabel, David Airlie, Daniel Vetter
Cc: dri-devel, linux-mediatek, linux-kernel, Guillaume Ranquet
On 02/02/2023 05:57, Chen-Yu Tsai wrote:
> The MediaTek DisplayPort interface bridge driver starts its interrupts
> as soon as its probed. However when the interrupts trigger the bridge
> might not have been attached to a DRM device. As drm_helper_hpd_irq_event()
> does not check whether the passed in drm_device is valid or not, a NULL
> pointer passed in results in a kernel NULL pointer dereference in it.
>
> Check whether the bridge is attached and only trigger an HPD event if
> it is.
>
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
> ---
> Changes since v1
> - Dropped prerequisite-patch-ids
> - Added Guillaume's Reviewed-by
>
> This applies on top of mediatek-drm-next.
>
> drivers/gpu/drm/mediatek/mtk_dp.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 1f94fcc144d3..a82f53e1a146 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -1823,7 +1823,8 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
> spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags);
>
> if (status & MTK_DP_THREAD_CABLE_STATE_CHG) {
> - drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
> + if (mtk_dp->bridge.dev)
> + drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
>
> if (!mtk_dp->train_info.cable_plugged_in) {
> mtk_dp_disable_sdp_aui(mtk_dp);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached
2023-02-02 4:57 [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached Chen-Yu Tsai
2023-02-02 9:14 ` AngeloGioacchino Del Regno
2023-02-02 9:56 ` Matthias Brugger
@ 2023-03-12 15:41 ` Chun-Kuang Hu
2 siblings, 0 replies; 4+ messages in thread
From: Chun-Kuang Hu @ 2023-03-12 15:41 UTC (permalink / raw)
To: Chen-Yu Tsai
Cc: Chun-Kuang Hu, Philipp Zabel, David Airlie, Daniel Vetter,
dri-devel, linux-mediatek, linux-kernel, Guillaume Ranquet
Hi, Chen-Yu:
Chen-Yu Tsai <wenst@chromium.org> 於 2023年2月2日 週四 下午12:57寫道:
>
> The MediaTek DisplayPort interface bridge driver starts its interrupts
> as soon as its probed. However when the interrupts trigger the bridge
> might not have been attached to a DRM device. As drm_helper_hpd_irq_event()
> does not check whether the passed in drm_device is valid or not, a NULL
> pointer passed in results in a kernel NULL pointer dereference in it.
>
> Check whether the bridge is attached and only trigger an HPD event if
> it is.
Applied to mediatek-drm-next [1], thanks.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next
Regards,
Chun-Kuang.
>
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Chen-Yu Tsai <wenst@chromium.org>
> Reviewed-by: Guillaume Ranquet <granquet@baylibre.com>
> ---
> Changes since v1
> - Dropped prerequisite-patch-ids
> - Added Guillaume's Reviewed-by
>
> This applies on top of mediatek-drm-next.
>
> drivers/gpu/drm/mediatek/mtk_dp.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index 1f94fcc144d3..a82f53e1a146 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -1823,7 +1823,8 @@ static irqreturn_t mtk_dp_hpd_event_thread(int hpd, void *dev)
> spin_unlock_irqrestore(&mtk_dp->irq_thread_lock, flags);
>
> if (status & MTK_DP_THREAD_CABLE_STATE_CHG) {
> - drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
> + if (mtk_dp->bridge.dev)
> + drm_helper_hpd_irq_event(mtk_dp->bridge.dev);
>
> if (!mtk_dp->train_info.cable_plugged_in) {
> mtk_dp_disable_sdp_aui(mtk_dp);
> --
> 2.39.1.456.gfc5497dd1b-goog
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-02-02 4:57 [PATCH v2] drm/mediatek: dp: Only trigger DRM HPD events if bridge is attached Chen-Yu Tsai
2023-02-02 9:14 ` AngeloGioacchino Del Regno
2023-02-02 9:56 ` Matthias Brugger
2023-03-12 15:41 ` Chun-Kuang Hu
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