[PATCH 4.19 040/229] can: kvaser_usb: Fix use of uninitialized completion

[Greg Kroah-Hartman]

From: Anssi Hannula <anssi.hannula@xxxxxxxxxx>

commit cd7f30e174d09a02ca2afa5ef093fb0f0352e0d8 upstream.

flush_comp is initialized when CMD_FLUSH_QUEUE is sent to the device and
completed when the device sends CMD_FLUSH_QUEUE_RESP.

This causes completion of uninitialized completion if the device sends
CMD_FLUSH_QUEUE_RESP before CMD_FLUSH_QUEUE is ever sent (e.g. as a
response to a flush by a previously bound driver, or a misbehaving
device).

Fix that by initializing flush_comp in kvaser_usb_init_one() like the
other completions.

This issue is only triggerable after RX URBs have been set up, i.e. the
interface has been opened at least once.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: aec5fb2268b7 ("can: kvaser_usb: Add support for Kvaser USB hydra family")
Tested-by: Jimmy Assarsson <extja@xxxxxxxxxx>
Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxxxxxx>
Signed-off-by: Jimmy Assarsson <extja@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20221010150829.199676-3-extja@xxxxxxxxxx
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c  |    1 +
 drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c |    2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -691,6 +691,7 @@ static int kvaser_usb_init_one(struct kv
 	init_usb_anchor(&priv->tx_submitted);
 	init_completion(&priv->start_comp);
 	init_completion(&priv->stop_comp);
+	init_completion(&priv->flush_comp);
 	priv->can.ctrlmode_supported = 0;
 
 	priv->dev = dev;
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
@@ -1886,7 +1886,7 @@ static int kvaser_usb_hydra_flush_queue(
 {
 	int err;
 
-	init_completion(&priv->flush_comp);
+	reinit_completion(&priv->flush_comp);
 
 	err = kvaser_usb_hydra_send_simple_cmd(priv->dev, CMD_FLUSH_QUEUE,
 					       priv->channel);