Commit ca4d8344 authored by Xu Yang's avatar Xu Yang Committed by Greg Kroah-Hartman
Browse files

usb: typec: tcpm: fix tcpm unregister port but leave a pending timer 



In current design, when the tcpm port is unregisterd, the kthread_worker
will be destroyed in the last step. Inside the kthread_destroy_worker(),
the worker will flush all the works and wait for them to end. However, if
one of the works calls hrtimer_start(), this hrtimer will be pending until
timeout even though tcpm port is removed. Once the hrtimer timeout, many
strange kernel dumps appear.

Thus, we can first complete kthread_destroy_worker(), then cancel all the
hrtimers. This will guarantee that no hrtimer is pending at the end.

Fixes: 3ed8e1c2 ("usb: typec: tcpm: Migrate workqueue to RT priority for processing events")
cc: <stable@vger.kernel.org>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Acked-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarXu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20211209101507.499096-1-xu.yang_2@nxp.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4c4e162d

drivers/usb/typec/tcpm/tcpm.c

+13 −5
Original line number Diff line number Diff line
@@ -324,6 +324,7 @@ struct tcpm_port { 


	bool attached;

	bool connected;

	bool registered;

	bool pd_supported;

	enum typec_port_type port_type;
@@ -6291,6 +6292,7 @@ static enum hrtimer_restart state_machine_timer_handler(struct hrtimer *timer) 
{

	struct tcpm_port *port = container_of(timer, struct tcpm_port, state_machine_timer);



	if (port->registered)

		kthread_queue_work(port->wq, &port->state_machine);

	return HRTIMER_NORESTART;

}
@@ -6299,6 +6301,7 @@ static enum hrtimer_restart vdm_state_machine_timer_handler(struct hrtimer *time 
{

	struct tcpm_port *port = container_of(timer, struct tcpm_port, vdm_state_machine_timer);



	if (port->registered)

		kthread_queue_work(port->wq, &port->vdm_state_machine);

	return HRTIMER_NORESTART;

}
@@ -6307,6 +6310,7 @@ static enum hrtimer_restart enable_frs_timer_handler(struct hrtimer *timer) 
{

	struct tcpm_port *port = container_of(timer, struct tcpm_port, enable_frs_timer);



	if (port->registered)

		kthread_queue_work(port->wq, &port->enable_frs);

	return HRTIMER_NORESTART;

}
@@ -6315,6 +6319,7 @@ static enum hrtimer_restart send_discover_timer_handler(struct hrtimer *timer) 
{

	struct tcpm_port *port = container_of(timer, struct tcpm_port, send_discover_timer);



	if (port->registered)

		kthread_queue_work(port->wq, &port->send_discover_work);

	return HRTIMER_NORESTART;

}
@@ -6403,6 +6408,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc) 
	typec_port_register_altmodes(port->typec_port,

				     &tcpm_altmode_ops, port,

				     port->port_altmode, ALTMODE_DISCOVERY_MAX);

	port->registered = true;



	mutex_lock(&port->lock);

	tcpm_init(port);
@@ -6424,6 +6430,9 @@ void tcpm_unregister_port(struct tcpm_port *port) 
{

	int i;



	port->registered = false;

	kthread_destroy_worker(port->wq);



	hrtimer_cancel(&port->send_discover_timer);

	hrtimer_cancel(&port->enable_frs_timer);

	hrtimer_cancel(&port->vdm_state_machine_timer);
@@ -6435,7 +6444,6 @@ void tcpm_unregister_port(struct tcpm_port *port) 
	typec_unregister_port(port->typec_port);

	usb_role_switch_put(port->role_sw);

	tcpm_debugfs_exit(port);

	kthread_destroy_worker(port->wq);

}

EXPORT_SYMBOL_GPL(tcpm_unregister_port);