[PATCH v4 1/2] media: i2c: ov02c10: Fix use-after-free in remove function

[Saikiran <bjsaikiran@gmail.com>]

The ov02c10_remove() function has a race condition where v4l2_ctrl_handler
and media_entity resources are freed before the device is powered off.
If userspace (e.g., PipeWire/WirePlumber) accesses the device during
removal, this causes a use-after-free leading to kernel oops with
"Execute from non-executable memory" errors.

The issue occurs because:
1. v4l2_ctrl_handler_free() is called first
2. Userspace may still have the device open
3. Control access triggers use-after-free
4. Device is powered off afterwards (too late)

Fix by reordering cleanup to disable runtime PM and power off the device
BEFORE freeing v4l2_ctrl_handler and media_entity resources. This ensures
the device is in a safe state before any resources are freed.

Call sequence after fix:
1. v4l2_async_unregister_subdev() - unregister from V4L2
2. pm_runtime_disable() - disable runtime PM
3. ov02c10_power_off() - power off device if needed
4. v4l2_subdev_cleanup() - clean up subdev
5. media_entity_cleanup() - clean up media entity
6. v4l2_ctrl_handler_free() - free control handler (safe now)

Tested-on: Lenovo Yoga Slim 7x (Snapdragon X Elite)
Fixes: 44f8901 ("media: i2c: add OmniVision OV02C10 sensor driver")
Cc: stable@vger.kernel.org
Reviewed-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Saikiran <bjsaikiran@gmail.com>
---
 drivers/media/i2c/ov02c10.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/i2c/ov02c10.c b/drivers/media/i2c/ov02c10.c
index cf93d36032e1..fa7cc48b769a 100644
--- a/drivers/media/i2c/ov02c10.c
+++ b/drivers/media/i2c/ov02c10.c
@@ -864,14 +864,14 @@ static void ov02c10_remove(struct i2c_client *client)
 	struct ov02c10 *ov02c10 = to_ov02c10(sd);
 
 	v4l2_async_unregister_subdev(sd);
-	v4l2_subdev_cleanup(sd);
-	media_entity_cleanup(&sd->entity);
-	v4l2_ctrl_handler_free(sd->ctrl_handler);
 	pm_runtime_disable(ov02c10->dev);
 	if (!pm_runtime_status_suspended(ov02c10->dev)) {
 		ov02c10_power_off(ov02c10->dev);
 		pm_runtime_set_suspended(ov02c10->dev);
 	}
+	v4l2_subdev_cleanup(sd);
+	media_entity_cleanup(&sd->entity);
+	v4l2_ctrl_handler_free(sd->ctrl_handler);
 }
 
 static int ov02c10_probe(struct i2c_client *client)
-- 
2.51.0