[PATCH] usb: gadget: udc: renesas_usb3: Add null pointer check in usb3_irq_epc_pipe0_setup()

[Wentao Liang <vulab@iscas.ac.cn>]

The function usb3_irq_epc_pipe0_setup() calls the function
usb3_get_request(), but does not check its return value which
is a null pointer if the function fails. This can result in a
null pointer dereference.

Add a null pointer check for usb3_get_request() to avoid null
pointer dereference when the function fails.

Fixes: 746bfe63bba3 ("usb: gadget: renesas_usb3: add support for Renesas USB3.0 peripheral controller")
Cc: stable@vger.kernel.org # v4.5
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 drivers/usb/gadget/udc/renesas_usb3.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/renesas_usb3.c b/drivers/usb/gadget/udc/renesas_usb3.c
index fce5c41d9f29..51f2dd8cbf91 100644
--- a/drivers/usb/gadget/udc/renesas_usb3.c
+++ b/drivers/usb/gadget/udc/renesas_usb3.c
@@ -1920,11 +1920,13 @@ static void usb3_irq_epc_pipe0_setup(struct renesas_usb3 *usb3)
 {
 	struct usb_ctrlrequest ctrl;
 	struct renesas_usb3_ep *usb3_ep = usb3_get_ep(usb3, 0);
+	struct renesas_usb3_request *usb3_req = usb3_get_request(usb3_ep);
 
 	/* Call giveback function if previous transfer is not completed */
+	if (!usb3_req)
+		return;
 	if (usb3_ep->started)
-		usb3_request_done(usb3_ep, usb3_get_request(usb3_ep),
-				  -ECONNRESET);
+		usb3_request_done(usb3_ep, usb3_req, -ECONNRESET);
 
 	usb3_p0_con_clear_buffer(usb3);
 	usb3_get_setup_data(usb3, &ctrl);
-- 
2.42.0.windows.2