[PATCH 4.14 167/193] virtio_console: initialize vtermno value for ports

From: Greg Kroah-Hartman
Date: Wed May 29 2019 - 23:36:47 EST


[ Upstream commit 4b0a2c5ff7215206ea6135a405f17c5f6fca7d00 ]

For regular serial ports we do not initialize value of vtermno
variable. A garbage value is assigned for non console ports.
The value can be observed as a random integer with [1].

[1] vim /sys/kernel/debug/virtio-ports/vport*p*

This patch initialize the value of vtermno for console serial
ports to '1' and regular serial ports are initiaized to '0'.

Reported-by: siliu@xxxxxxxxxx
Signed-off-by: Pankaj Gupta <pagupta@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/char/virtio_console.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index a089474cb046a..65454acd4b974 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -75,7 +75,7 @@ struct ports_driver_data {
/* All the console devices handled by this driver */
struct list_head consoles;
};
-static struct ports_driver_data pdrvdata;
+static struct ports_driver_data pdrvdata = { .next_vtermno = 1};

static DEFINE_SPINLOCK(pdrvdata_lock);
static DECLARE_COMPLETION(early_console_added);
@@ -1422,6 +1422,7 @@ static int add_port(struct ports_device *portdev, u32 id)
port->async_queue = NULL;

port->cons.ws.ws_row = port->cons.ws.ws_col = 0;
+ port->cons.vtermno = 0;

port->host_connected = port->guest_connected = false;
port->stats = (struct port_stats) { 0 };
--
2.20.1