usb: udc: Add trace event for usb_gadget_set_state

[ Upstream commit 7bf1158 ]

While the userspace program can be notified of gadget state changes,
timing issue can lead to missed transitions when reading the state
value.

Introduce a trace event for usb_gadget_set_state to reliably track state
transitions.

Signed-off-by: Kuen-Han Tsai <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Stable-dep-of: baeb66f ("usb: gadget: udc: fix use-after-free in usb_gadget_state_work")
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Kuen-Han Tsai

drivers/usb/gadget/udc/core.c

@@ -1123,6 +1123,7 @@ void usb_gadget_set_state(struct usb_gadget *gadget,
 {
 	gadget->state = state;
 	schedule_work(&gadget->work);
+	trace_usb_gadget_set_state(gadget, 0);
 }
 EXPORT_SYMBOL_GPL(usb_gadget_set_state);
 

drivers/usb/gadget/udc/trace.h

@@ -81,6 +81,11 @@ DECLARE_EVENT_CLASS(udc_log_gadget,
 		__entry->ret)
 );
 
+DEFINE_EVENT(udc_log_gadget, usb_gadget_set_state,
+	TP_PROTO(struct usb_gadget *g, int ret),
+	TP_ARGS(g, ret)
+);
+
 DEFINE_EVENT(udc_log_gadget, usb_gadget_frame_number,
 	TP_PROTO(struct usb_gadget *g, int ret),
 	TP_ARGS(g, ret)