[PATCH] media: malic55: Fix possible ERR_PTR deference in enable_streams

[Alper Ak <alperyasinak1@gmail.com>]

The media_pad_remote_pad_unique() function returns either a valid
pointer or an ERR_PTR() on failure (-ENOTUNIQ if multiple links are
enabled, -ENOLINK if no connected pad is found). The return value
was assigned directly to isp->remote_src and dereferenced in the
next line without checking for errors, which could lead to an
ERR_PTR dereference.

Add proper error checking with IS_ERR() before dereferencing the
pointer. Also set isp->remote_src to NULL on error to maintain
consistency with other error paths in the function.

Fixes: d5f281f3dd29 ("media: mali-c55: Add Mali-C55 ISP driver")
Signed-off-by: Alper Ak <alperyasinak1@gmail.com>
---
 drivers/media/platform/arm/mali-c55/mali-c55-isp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
index 497f25fbdd13..c7225e9c8df7 100644
--- a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
+++ b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
@@ -360,6 +360,13 @@ static int mali_c55_isp_enable_streams(struct v4l2_subdev *sd,
 
 	sink_pad = &isp->pads[MALI_C55_ISP_PAD_SINK_VIDEO];
 	isp->remote_src = media_pad_remote_pad_unique(sink_pad);
+	if (IS_ERR(isp->remote_src))  {
+		ret = PTR_ERR(isp->remote_src);
+		dev_err(mali_c55->dev, "Failed to get remote source pad: %d\n", ret);
+		isp->remote_src = NULL;
+		return ret;
+	}
+
 	src_sd = media_entity_to_v4l2_subdev(isp->remote_src->entity);
 
 	isp->frame_sequence = 0;
-- 
2.43.0