[PATCH] usb: dwc3: gadget: Fix null pointer dereference

From: Albert Wang
Date: Wed May 04 2022 - 03:28:13 EST


There are still race conditions to hit the null pointer deference
with my previous commit. So I re-write the code to dereference the
pointer right after checking it is not null.

Fixes: 26288448120b ("usb: dwc3: gadget: Fix null pointer exception")

Signed-off-by: Albert Wang <albertccwang@xxxxxxxxxx>
---
drivers/usb/dwc3/gadget.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 19477f4bbf54..f2792968afd9 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -3366,15 +3366,14 @@ static bool dwc3_gadget_endpoint_trbs_complete(struct dwc3_ep *dep,
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)
goto out;

- if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
+ if (!dep->endpoint.desc)
+ return no_started_trb;
+ else if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
list_empty(&dep->started_list) &&
(list_empty(&dep->pending_list) || status == -EXDEV))
dwc3_stop_active_transfer(dep, true, true);
--
2.36.0.464.gb9c8b46e94-goog