[PATCH] media: v4l2-fwnode: Fix subdev owner overwritten in v4l2_async_register_subdev_sensor()

[Mirela Rabulea]

The v4l2 helper v4l2_async_register_subdev_sensor() calls
v4l2_async_register_subdev(), which is a macro that expands to
__v4l2_async_register_subdev(sd,THIS_MODULE). Since the macro is expanded
inside v4l2-fwnode.c, THIS_MODULE resolves to the v4l2-fwnode module
rather than the sensor driver module that originally set sd->owner. When
v4l2-fwnode is built-in, THIS_MODULE evaluates to NULL, which then
overwrites the sensor driver's owner with NULL.

This causes the problem that the sensor module's reference count is never
incremented during async registration, so the module can be removed while
the subdevice is still in use by a notifier (e.g., a CSI-2 receiver
bridge driver).

Fix this by calling __v4l2_async_register_subdev() directly with
sd->owner, which preserves the module owner that the sensor driver set
during probe via v4l2_i2c_subdev_init() or direct assignment.

Fixes: aef69d54755d ("media: v4l: fwnode: Add a convenience function for registering sensors")

Signed-off-by: Mirela Rabulea <mirela.rabulea@xxxxxxx>
---
 drivers/media/v4l2-core/v4l2-fwnode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/v4l2-core/v4l2-fwnode.c b/drivers/media/v4l2-core/v4l2-fwnode.c
index 77f3298821b5..57284b7adddf 100644
--- a/drivers/media/v4l2-core/v4l2-fwnode.c
+++ b/drivers/media/v4l2-core/v4l2-fwnode.c
@@ -1282,7 +1282,7 @@ int v4l2_async_register_subdev_sensor(struct v4l2_subdev *sd)
 	if (ret < 0)
 		goto out_cleanup;
 
-	ret = v4l2_async_register_subdev(sd);
+	ret = __v4l2_async_register_subdev(sd, sd->owner);
 	if (ret < 0)
 		goto out_unregister;
 
-- 
2.43.0