From: Jack Pham quic_jackp@quicinc.com
[ Upstream commit fac4b8633fd682ecc8e9cff61cb3e33374a1c7e5 ]
During ucsi_unregister() when destroying a connector's workqueue, there may still be pending delayed work items that haven't been scheduled yet. Because queue_delayed_work() uses a separate timer to schedule a work item, the destroy_workqueue() call is not aware of any pending items. Hence when a pending item's timer expires it would then try to queue on a dangling workqueue pointer.
Fix this by keeping track of all work items in a list, so that prior to destroying the workqueue any pending items can be flushed. Do this by calling mod_delayed_work() as that will cause pending items to get queued immediately, which then allows the ensuing destroy_workqueue() to implicitly drain all currently queued items to completion and free themselves.
Fixes: b9aa02ca39a4 ("usb: typec: ucsi: Add polling mechanism for partner tasks like alt mode checking") Suggested-by: Heikki Krogerus heikki.krogerus@linux.intel.com Co-developed-by: Linyu Yuan quic_linyyuan@quicinc.com Signed-off-by: Linyu Yuan quic_linyyuan@quicinc.com Signed-off-by: Jack Pham quic_jackp@quicinc.com Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Link: https://lore.kernel.org/r/20230110071218.26261-1-quic_jackp@quicinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/typec/ucsi/ucsi.c | 24 +++++++++++++++++++++--- drivers/usb/typec/ucsi/ucsi.h | 1 + 2 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c index eabe519013e7..1292241d581a 100644 --- a/drivers/usb/typec/ucsi/ucsi.c +++ b/drivers/usb/typec/ucsi/ucsi.c @@ -187,6 +187,7 @@ EXPORT_SYMBOL_GPL(ucsi_send_command);
struct ucsi_work { struct delayed_work work; + struct list_head node; unsigned long delay; unsigned int count; struct ucsi_connector *con; @@ -202,6 +203,7 @@ static void ucsi_poll_worker(struct work_struct *work) mutex_lock(&con->lock);
if (!con->partner) { + list_del(&uwork->node); mutex_unlock(&con->lock); kfree(uwork); return; @@ -209,10 +211,12 @@ static void ucsi_poll_worker(struct work_struct *work)
ret = uwork->cb(con);
- if (uwork->count-- && (ret == -EBUSY || ret == -ETIMEDOUT)) + if (uwork->count-- && (ret == -EBUSY || ret == -ETIMEDOUT)) { queue_delayed_work(con->wq, &uwork->work, uwork->delay); - else + } else { + list_del(&uwork->node); kfree(uwork); + }
mutex_unlock(&con->lock); } @@ -236,6 +240,7 @@ static int ucsi_partner_task(struct ucsi_connector *con, uwork->con = con; uwork->cb = cb;
+ list_add_tail(&uwork->node, &con->partner_tasks); queue_delayed_work(con->wq, &uwork->work, delay);
return 0; @@ -1056,6 +1061,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) INIT_WORK(&con->work, ucsi_handle_connector_change); init_completion(&con->complete); mutex_init(&con->lock); + INIT_LIST_HEAD(&con->partner_tasks); con->num = index + 1; con->ucsi = ucsi;
@@ -1420,8 +1426,20 @@ void ucsi_unregister(struct ucsi *ucsi) ucsi_unregister_altmodes(&ucsi->connector[i], UCSI_RECIPIENT_CON); ucsi_unregister_port_psy(&ucsi->connector[i]); - if (ucsi->connector[i].wq) + + if (ucsi->connector[i].wq) { + struct ucsi_work *uwork; + + mutex_lock(&ucsi->connector[i].lock); + /* + * queue delayed items immediately so they can execute + * and free themselves before the wq is destroyed + */ + list_for_each_entry(uwork, &ucsi->connector[i].partner_tasks, node) + mod_delayed_work(ucsi->connector[i].wq, &uwork->work, 0); + mutex_unlock(&ucsi->connector[i].lock); destroy_workqueue(ucsi->connector[i].wq); + } typec_unregister_port(ucsi->connector[i].port); }
diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h index c968474ee547..60ce9fb6e745 100644 --- a/drivers/usb/typec/ucsi/ucsi.h +++ b/drivers/usb/typec/ucsi/ucsi.h @@ -322,6 +322,7 @@ struct ucsi_connector { struct work_struct work; struct completion complete; struct workqueue_struct *wq; + struct list_head partner_tasks;
struct typec_port *port; struct typec_partner *partner;