[media] rc-core: race condition during ir_raw_event_register()
A rc device can call ir_raw_event_handle() after rc_allocate_device(),
but before rc_register_device() has completed. This is racey because
rcdev->raw is set before rcdev->raw->thread has a valid value.
Cc: stable@kernel.org
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c
index 90f66dc7..a2fc1a1 100644
--- a/drivers/media/rc/rc-ir-raw.c
+++ b/drivers/media/rc/rc-ir-raw.c
@@ -211,7 +211,7 @@
*/
void ir_raw_event_handle(struct rc_dev *dev)
{
- if (!dev->raw)
+ if (!dev->raw || !dev->raw->thread)
return;
wake_up_process(dev->raw->thread);
@@ -490,6 +490,7 @@
{
int rc;
struct ir_raw_handler *handler;
+ struct task_struct *thread;
if (!dev)
return -EINVAL;
@@ -507,13 +508,15 @@
* because the event is coming from userspace
*/
if (dev->driver_type != RC_DRIVER_IR_RAW_TX) {
- dev->raw->thread = kthread_run(ir_raw_event_thread, dev->raw,
- "rc%u", dev->minor);
+ thread = kthread_run(ir_raw_event_thread, dev->raw, "rc%u",
+ dev->minor);
- if (IS_ERR(dev->raw->thread)) {
- rc = PTR_ERR(dev->raw->thread);
+ if (IS_ERR(thread)) {
+ rc = PTR_ERR(thread);
goto out;
}
+
+ dev->raw->thread = thread;
}
mutex_lock(&ir_raw_handler_lock);