[PATCH 5.10 009/121] usb: dwc3: gadget: Fix null pointer exception

[Greg Kroah-Hartman]

From: Albert Wang <albertccwang@xxxxxxxxxx>

commit 26288448120b28af1dfd85a6fa6b6d55a16c7f2f upstream.

In the endpoint interrupt functions
dwc3_gadget_endpoint_transfer_in_progress() and
dwc3_gadget_endpoint_trbs_complete() will dereference the endpoint
descriptor. But it could be cleared in __dwc3_gadget_ep_disable()
when accessory disconnected. So we need to check whether it is null
or not before dereferencing it.

Fixes: f09ddcfcb8c5 ("usb: dwc3: gadget: Prevent EP queuing while stopping transfers")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Reviewed-by: Jack Pham <quic_jackp@xxxxxxxxxxx>
Signed-off-by: Albert Wang <albertccwang@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211109092642.3507692-1-albertccwang@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/dwc3/gadget.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2918,6 +2918,9 @@ static bool dwc3_gadget_endpoint_trbs_co
 	struct dwc3		*dwc = dep->dwc;
 	bool			no_started_trb = true;
 
+	if (!dep->endpoint.desc)
+		return no_started_trb;
+
 	dwc3_gadget_ep_cleanup_completed_requests(dep, event, status);
 
 	if (dep->flags & DWC3_EP_END_TRANSFER_PENDING)
@@ -2965,6 +2968,9 @@ static void dwc3_gadget_endpoint_transfe
 {
 	int status = 0;
 
+	if (!dep->endpoint.desc)
+		return;
+
 	if (usb_endpoint_xfer_isoc(dep->endpoint.desc))
 		dwc3_gadget_endpoint_frame_from_event(dep, event);