virtio: console: add locking in port unplug path

Port unplug can race with close() in port_fops_release().
port_fops_release() already takes the necessary locks, ensure
unplug_port() does that too.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 601962b1708b..3572c5a92e8e 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1542,6 +1542,7 @@ static void unplug_port(struct port *port)
         list_del(&port->list);
         spin_unlock_irq(&port->portdev->ports_lock);
 
+        spin_lock_irq(&port->inbuf_lock);
         if (port->guest_connected) {
                 port->guest_connected = false;
                 port->host_connected = false;
@@ -1550,6 +1551,7 @@ static void unplug_port(struct port *port)
                 /* Let the app know the port is going down. */
                 send_sigio_to_port(port);
         }
+        spin_unlock_irq(&port->inbuf_lock);
 
         if (is_console_port(port)) {
                 spin_lock_irq(&pdrvdata_lock);