[PATCH] media: rockchip: rkcif: Add missing MUST_CONNECT flag to pads

[Dang Huynh]

The pads missed checks for connected devices which may a null dereference
when the stream is enabled.

Unable to handle kernel NULL pointer dereference at virtual address
0000000000000020
pc : rkcif_interface_enable_streams+0x48/0xf0
lr : rkcif_interface_enable_streams+0x44/0xf0
Call trace:
 rkcif_interface_enable_streams+0x48/0xf0
 v4l2_subdev_enable_streams+0x26c/0x3f0
 rkcif_stream_start_streaming+0x140/0x278
 vb2_start_streaming+0x74/0x188
 vb2_core_streamon+0xe0/0x1d8
 vb2_ioctl_streamon+0x60/0xa8
 v4l_streamon+0x2c/0x40
 __video_do_ioctl+0x34c/0x400
 video_usercopy+0x2d0/0x800
 video_ioctl2+0x20/0x60
 v4l2_ioctl+0x48/0x78

Fixes: 501802e2ad51 ("media: rockchip: rkcif: add abstraction for dma blocks")
Fixes: 85411d17bee9 ("media: rockchip: rkcif: add abstraction for interface and crop blocks")
Signed-off-by: Dang Huynh <dang.huynh at mainlining.org>
---
The RKCIF driver missed MEDIA_PAD_FL_MUST_CONNECT, which causes a null
dereference when the stream starts if the links are misconfigured.
---
 drivers/media/platform/rockchip/rkcif/rkcif-interface.c | 3 ++-
 drivers/media/platform/rockchip/rkcif/rkcif-stream.c    | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/rockchip/rkcif/rkcif-interface.c b/drivers/media/platform/rockchip/rkcif/rkcif-interface.c
index 523103872b7a..414a9980cf2e 100644
--- a/drivers/media/platform/rockchip/rkcif/rkcif-interface.c
+++ b/drivers/media/platform/rockchip/rkcif/rkcif-interface.c
@@ -378,7 +378,8 @@ int rkcif_interface_register(struct rkcif_device *rkcif,
 		snprintf(sd->name, sizeof(sd->name), "rkcif-mipi%d",
 			 interface->index - RKCIF_MIPI_BASE);
 
-	pads[RKCIF_IF_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
+	pads[RKCIF_IF_PAD_SINK].flags = MEDIA_PAD_FL_SINK |
+					MEDIA_PAD_FL_MUST_CONNECT;
 	pads[RKCIF_IF_PAD_SRC].flags = MEDIA_PAD_FL_SOURCE;
 	ret = media_entity_pads_init(&sd->entity, RKCIF_IF_PAD_MAX, pads);
 	if (ret)
diff --git a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
index e00010a91e8b..201542b55f00 100644
--- a/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
+++ b/drivers/media/platform/rockchip/rkcif/rkcif-stream.c
@@ -555,7 +555,7 @@ int rkcif_stream_register(struct rkcif_device *rkcif,
 	vdev->vfl_dir = VFL_DIR_RX;
 	video_set_drvdata(vdev, stream);
 
-	stream->pad.flags = MEDIA_PAD_FL_SINK;
+	stream->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
 
 	stream->pix.height = CIF_MIN_HEIGHT;
 	stream->pix.width = CIF_MIN_WIDTH;

---
base-commit: 3f24e4edcd1b8981c6b448ea2680726dedd87279
change-id: 20260129-rkcif-null-fbc0be41f81a

Best regards,
-- 
Dang Huynh <dang.huynh at mainlining.org>