virtio: console: Check if portdev is valid in send_control_msg()
A portdev may have been hot-unplugged while a port was open()ed. Skip
sending control messages when the portdev isn't valid.
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index e15dbe7..e1d382b 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -410,7 +410,10 @@
static ssize_t send_control_msg(struct port *port, unsigned int event,
unsigned int value)
{
- return __send_control_msg(port->portdev, port->id, event, value);
+ /* Did the port get unplugged before userspace closed it? */
+ if (port->portdev)
+ return __send_control_msg(port->portdev, port->id, event, value);
+ return 0;
}
/* Callers must take the port->outvq_lock */
