On Sat, Jun 19, 2021 at 11:43:08PM +0800, Linyu Yuan wrote: > currently most gadget driver have a pointer to save > struct usb_gadget_driver from upper layer, > it allow upper layer set and unset of the pointer. > > there is race that upper layer unset the pointer first, > but gadget driver use the pointer later, > and it cause system crash due to NULL pointer access. This race has already been fixed in Greg's usb-next branch. See commit 7dc0c55e9f30 ("USB: UDC core: Add udc_async_callbacks gadget op") and following commits 04145a03db9d ("USB: UDC: Implement udc_async_callbacks in dummy-hcd") and b42e8090ba93 ("USB: UDC: Implement udc_async_callbacks in net2280"). You just need to write a corresponding patch implementing the async_callbacks op for dwc3. Alan Stern