usb: typec: ucsi: displayport: Fix NULL pointer access

commit 312d796 upstream.

This patch ensures that the UCSI driver waits for all pending tasks in the
ucsi_displayport_work workqueue to finish executing before proceeding with
the partner removal.

Cc: stable <[email protected]>
Fixes: af8622f ("usb: typec: ucsi: Support for DisplayPort alt mode")
Signed-off-by: Andrei Kuchynski <[email protected]>
Reviewed-by: Heikki Krogerus <[email protected]>
Reviewed-by: Benson Leung <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
(cherry picked from commit 5ad298d6d4aebe1229adba6427e417e89a5208d8)
Signed-off-by: Jack Vogel <[email protected]>

Author: Andrei Kuchynski

drivers/usb/typec/ucsi/displayport.c

@@ -296,6 +296,8 @@ void ucsi_displayport_remove_partner(struct typec_altmode *alt)
 	if (!dp)
 		return;
 
+	cancel_work_sync(&dp->work);
+
 	dp->data.conf = 0;
 	dp->data.status = 0;
 	dp->initialized = false;