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>

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 8c99bf1..e3fb529 100644 (file)
--- 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);