[PATCH] phy: tegra: xusb: Fix use-after-free issue

[Haotien Hsu]

From: EJ Hsu <ejh at nvidia.com>

For the dual-role port, it will assign the phy dev to usb-phy dev and
use the port dev driver as the dev driver of usb-phy.

When we try to destroy the port dev, it will destroy its dev driver
as well. But we did not remove the reference from usb-phy dev. This
might cause the use-after-free issue in KASAN.

Fixes: e8f7d2f409a1 ("phy: tegra: xusb: Add usb-phy support")
Cc: stable at vger.kernel.org

Signed-off-by: EJ Hsu <ejh at nvidia.com>
Signed-off-by: Haotien Hsu <haotienh at nvidia.com>
---
 drivers/phy/tegra/xusb.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/phy/tegra/xusb.c b/drivers/phy/tegra/xusb.c
index 78045bd6c214..515298a9a433 100644
--- a/drivers/phy/tegra/xusb.c
+++ b/drivers/phy/tegra/xusb.c
@@ -563,13 +563,6 @@ static int tegra_xusb_port_init(struct tegra_xusb_port *port,
 
 static void tegra_xusb_port_unregister(struct tegra_xusb_port *port)
 {
-	if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
-		of_platform_depopulate(&port->dev);
-		usb_role_switch_unregister(port->usb_role_sw);
-		cancel_work_sync(&port->usb_phy_work);
-		usb_remove_phy(&port->usb_phy);
-	}
-
 	if (port->ops->remove)
 		port->ops->remove(port);
 
@@ -832,6 +825,14 @@ void tegra_xusb_usb2_port_remove(struct tegra_xusb_port *port)
 {
 	struct tegra_xusb_usb2_port *usb2 = to_usb2_port(port);
 
+	if (!IS_ERR_OR_NULL(port->usb_role_sw)) {
+		of_platform_depopulate(&port->dev);
+		usb_role_switch_unregister(port->usb_role_sw);
+		cancel_work_sync(&port->usb_phy_work);
+		usb_remove_phy(&port->usb_phy);
+		port->usb_phy.dev->driver = NULL;
+	}
+
 	regulator_put(usb2->supply);
 }
 
-- 
2.25.1