[PATCH 03/14] virtio: console: Check if portdev is valid in send_control_msg()

Amit Shah
Thu, 02 Sep 2010 12:41:42 -0000

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 at redhat.com>
---
 drivers/char/virtio_console.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 0f115b4..5cd5374 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -410,7 +410,10 @@ static ssize_t __send_control_msg(struct ports_device
*portdev, u32 port_id,
 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 */
--
1.7.2.2