[PATCH 10/10] virtio: console: fix locking around send_sigio_to_port()

[Amit Shah <amit.shah@redhat.com>]

send_sigio_to_port() checks the value of guest_connected, which we
always modify under the inbuf_lock; make sure invocations of
send_sigio_to_port() have take the inbuf_lock around the call.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 drivers/char/virtio_console.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index b174945..3b9b541 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1674,7 +1674,9 @@ static void handle_control_message(struct ports_device *portdev,
 		 * If the guest is connected, it'll be interested in
 		 * knowing the host connection state changed.
 		 */
+		spin_lock_irq(&port->inbuf_lock);
 		send_sigio_to_port(port);
+		spin_unlock_irq(&port->inbuf_lock);
 		break;
 	case VIRTIO_CONSOLE_PORT_NAME:
 		/*
@@ -1794,13 +1796,13 @@ static void in_intr(struct virtqueue *vq)
 	if (!port->guest_connected && !is_rproc_serial(port->portdev->vdev))
 		discard_port_data(port);
 
+	/* Send a SIGIO indicating new data in case the process asked for it */
+	send_sigio_to_port(port);
+
 	spin_unlock_irqrestore(&port->inbuf_lock, flags);
 
 	wake_up_interruptible(&port->waitqueue);
 
-	/* Send a SIGIO indicating new data in case the process asked for it */
-	send_sigio_to_port(port);
-
 	if (is_console_port(port) && hvc_poll(port->cons.hvc))
 		hvc_kick();
 }
-- 
1.8.1.4