virtio: console: Fix crash when hot-unplugging a port and read is blocked

When removing a port we don't check if a program was blocked for read.
This leads to a crash when SIGTERM is sent to the program after
hot-unplugging the port.

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

1 files changed, 7 insertions, 3 deletions

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 8c99bf1b5e9f..e3fb5296cf25 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1099,6 +1099,13 @@ static int remove_port(struct port *port)
 {
         struct port_buffer *buf;
 
+        if (port->guest_connected) {
+                port->guest_connected = false;
+                port->host_connected = false;
+                wake_up_interruptible(&port->waitqueue);
+                send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
+        }
+
         spin_lock_irq(&port->portdev->ports_lock);
         list_del(&port->list);
         spin_unlock_irq(&port->portdev->ports_lock);
@@ -1120,9 +1127,6 @@ static int remove_port(struct port *port)
                 hvc_remove(port->cons.hvc);
 #endif
         }
-        if (port->guest_connected)
-                send_control_msg(port, VIRTIO_CONSOLE_PORT_OPEN, 0);
-
         sysfs_remove_group(&port->dev->kobj, &port_attribute_group);
         device_destroy(pdrvdata.class, port->dev->devt);
         cdev_del(&port->cdev);