[PATCH 5.2 047/144] can: flexcan: fix an use-after-free in flexcan_setup_stop_mode()

[Greg Kroah-Hartman]

From: Wen Yang <wen.yang99@xxxxxxxxxx>

commit e9f2a856e102fa27715b94bcc2240f686536d29b upstream.

The gpr_np variable is still being used in dev_dbg() after the
of_node_put() call, which may result in use-after-free.

Fixes: de3578c198c6 ("can: flexcan: add self wakeup support")
Signed-off-by: Wen Yang <wen.yang99@xxxxxxxxxx>
Cc: linux-stable <stable@xxxxxxxxxxxxxxx> # >= v5.0
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/can/flexcan.c |    8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -1455,10 +1455,10 @@ static int flexcan_setup_stop_mode(struc
 
 	priv = netdev_priv(dev);
 	priv->stm.gpr = syscon_node_to_regmap(gpr_np);
-	of_node_put(gpr_np);
 	if (IS_ERR(priv->stm.gpr)) {
 		dev_dbg(&pdev->dev, "could not find gpr regmap\n");
-		return PTR_ERR(priv->stm.gpr);
+		ret = PTR_ERR(priv->stm.gpr);
+		goto out_put_node;
 	}
 
 	priv->stm.req_gpr = out_val[1];
@@ -1473,7 +1473,9 @@ static int flexcan_setup_stop_mode(struc
 
 	device_set_wakeup_capable(&pdev->dev, true);
 
-	return 0;
+out_put_node:
+	of_node_put(gpr_np);
+	return ret;
 }
 
 static const struct of_device_id flexcan_of_match[] = {