[PATCH v3 11/13] media: rc: Use after free in ir_raw_event_handle()

[Sean Young <sean@mess.org>]

If rc_unregister_device() is called while IR is being processed, then
ir_raw_event_handle() could call wake_up_process(dev->raw->thread)
after kthread_stop(dev->raw->thread).

Fixes: dccc0c3ddf8f ("media: rc: fix race between unregister and urb/irq callbacks")
Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/rc-ir-raw.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c
index ba24c2f22d39..f066176c9f37 100644
--- a/drivers/media/rc/rc-ir-raw.c
+++ b/drivers/media/rc/rc-ir-raw.c
@@ -637,6 +637,7 @@ int ir_raw_event_register(struct rc_dev *dev)
 	if (IS_ERR(thread))
 		return PTR_ERR(thread);
 
+	get_task_struct(thread);
 	dev->raw->thread = thread;
 
 	mutex_lock(&ir_raw_handler_lock);
@@ -648,8 +649,12 @@ int ir_raw_event_register(struct rc_dev *dev)
 
 void ir_raw_event_free(struct rc_dev *dev)
 {
-	kfree(dev->raw);
-	dev->raw = NULL;
+	if (dev->raw) {
+		if (dev->raw->thread)
+			put_task_struct(dev->raw->thread);
+		kfree(dev->raw);
+		dev->raw = NULL;
+	}
 }
 
 void ir_raw_event_unregister(struct rc_dev *dev)
-- 
2.55.0