@@ -3366,14 +3366,19 @@ 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;
-
+ /*
+ * This function eventually leads to dwc3_giveback() which unlocks
+ * the dwc->lock and relocks afterwards. This actually creates a
+ * a window for a race to happen.
+ */
dwc3_gadget_ep_cleanup_completed_requests(dep, event, status);
if (dep->flags & DWC3_EP_END_TRANSFER_PENDING)
goto out;
+ if (!dep->endpoint.desc)
+ return no_started_trb;
+
if (usb_endpoint_xfer_isoc(dep->endpoint.desc) &&
list_empty(&dep->started_list) &&
(list_empty(&dep->pending_list) || status == -EXDEV))
After inspecting further, we do see the locking is implicit, with the main gotcha being the unlock/re-lock. That creates a window for a race to happen. This change moves the NULL check to be adjacent to where to it's used and after the window is "closed". Fixes: 26288448120b ("usb: dwc3: gadget: Fix null pointer exception") Signed-off-by: Albert Wang <albertccwang@google.com> --- v2: Remove redundant 'else' and add additional comments and more descriptive commit text drivers/usb/dwc3/gadget.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)