[PATCH v4 02/15] can: kvaser_usb: Fix use of uninitialized completion

[Jimmy Assarsson <extja@kvaser.com>]

From: Anssi Hannula <anssi.hannula@bitwise.fi>

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@vger.kernel.org
Fixes: aec5fb2268b7 ("can: kvaser_usb: Add support for Kvaser USB hydra family")
Tested-by: Jimmy Assarsson <extja@kvaser.com>
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Signed-off-by: Jimmy Assarsson <extja@kvaser.com>
---
Changes in v4:
 - No changes

Changes in v3:
 - Rebased on 1d5eeda23f36 ("can: kvaser_usb: advertise timestamping capabilities and add ioctl support")
 - Add stable to CC
 - Add S-o-b

Changes in v2:
  - Rebased on b3b6df2c56d8 ("can: kvaser_usb: kvaser_usb_leaf: fix bittiming limits")

 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(-)

diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
index 824cab80aa02..c2bce6773adc 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c
@@ -729,6 +729,7 @@ static int kvaser_usb_init_one(struct kvaser_usb *dev, int channel)
 	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;
diff --git a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
index dd65c101bfb8..3dcd35979e6f 100644
--- a/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
+++ b/drivers/net/can/usb/kvaser_usb/kvaser_usb_hydra.c
@@ -1916,7 +1916,7 @@ static int kvaser_usb_hydra_flush_queue(struct kvaser_usb_net_priv *priv)
 {
 	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);
-- 
2.37.3