This is a note to let you know that I've just added the patch titled

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

to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From ca4d8344a72b91fb9d4c8bfbc22204b4c09c5d8f Mon Sep 17 00:00:00 2001

From: Xu Yang xu.yang_2@nxp.com Date: Thu, 9 Dec 2021 18:15:07 +0800 Subject: 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: 3ed8e1c2ac99 ("usb: typec: tcpm: Migrate workqueue to RT priority for processing events") cc: stable@vger.kernel.org Reviewed-by: Guenter Roeck linux@roeck-us.net Acked-by: Heikki Krogerus heikki.krogerus@linux.intel.com Signed-off-by: Xu Yang xu.yang_2@nxp.com Link: https://lore.kernel.org/r/20211209101507.499096-1-xu.yang_2@nxp.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/typec/tcpm/tcpm.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 6010b9901126..59d4fa2443f2 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -324,6 +324,7 @@ struct tcpm_port {

bool attached; bool connected; + bool registered; bool pd_supported; enum typec_port_type port_type;

@@ -6291,7 +6292,8 @@ static enum hrtimer_restart state_machine_timer_handler(struct hrtimer *timer) { struct tcpm_port *port = container_of(timer, struct tcpm_port, state_machine_timer);

- kthread_queue_work(port->wq, &port->state_machine); + if (port->registered) + kthread_queue_work(port->wq, &port->state_machine); return HRTIMER_NORESTART; }

@@ -6299,7 +6301,8 @@ 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);

- kthread_queue_work(port->wq, &port->vdm_state_machine); + if (port->registered) + kthread_queue_work(port->wq, &port->vdm_state_machine); return HRTIMER_NORESTART; }

@@ -6307,7 +6310,8 @@ static enum hrtimer_restart enable_frs_timer_handler(struct hrtimer *timer) { struct tcpm_port *port = container_of(timer, struct tcpm_port, enable_frs_timer);

- kthread_queue_work(port->wq, &port->enable_frs); + if (port->registered) + kthread_queue_work(port->wq, &port->enable_frs); return HRTIMER_NORESTART; }

@@ -6315,7 +6319,8 @@ static enum hrtimer_restart send_discover_timer_handler(struct hrtimer *timer) { struct tcpm_port *port = container_of(timer, struct tcpm_port, send_discover_timer);

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