From: Albert Wang albertccwang@google.com
commit 3c5880745b4439ac64eccdb040e37fc1cc4c5406 upstream.
When dwc3_gadget_ep_cleanup_completed_requests() called to dwc3_gadget_giveback() where the dwc3 lock is released, other thread is able to execute. In this situation, usb_ep_disable() gets the chance to clear endpoint descriptor pointer which leds to the null pointer dereference problem. So needs to move the null pointer check to a proper place.
Example call stack:
Thread#1: dwc3_thread_interrupt() spin_lock -> dwc3_process_event_buf() -> dwc3_process_event_entry() -> dwc3_endpoint_interrupt() -> dwc3_gadget_endpoint_trbs_complete() -> dwc3_gadget_ep_cleanup_completed_requests() ... -> dwc3_giveback() spin_unlock Thread#2 executes
Thread#2: configfs_composite_disconnect() -> __composite_disconnect() -> ffs_func_disable() -> ffs_func_set_alt() -> ffs_func_eps_disable() -> usb_ep_disable() wait for dwc3 spin_lock Thread#1 released lock clear endpoint.desc
Fixes: 26288448120b ("usb: dwc3: gadget: Fix null pointer exception") Cc: stable stable@kernel.org Signed-off-by: Albert Wang albertccwang@google.com Link: https://lore.kernel.org/r/20220518061315.3359198-1-albertccwang@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc3/gadget.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -2960,14 +2960,14 @@ 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) 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))