[PATCH 6.1.y 1/2] usb: udc: Add trace event for usb_gadget_set_state

[Sasha Levin <sashal@kernel.org>]

From: Kuen-Han Tsai <khtsai@google.com>

[ Upstream commit 7bf1158514e410310aec975e630cec99d4e4092f ]

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 <khtsai@google.com>
Link: https://lore.kernel.org/r/20250818082722.2952867-1-khtsai@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stable-dep-of: baeb66fbd420 ("usb: gadget: udc: fix use-after-free in usb_gadget_state_work")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/usb/gadget/udc/core.c  | 1 +
 drivers/usb/gadget/udc/trace.h | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index d98da3c44ff5e..37f83606477fc 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/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);
 
diff --git a/drivers/usb/gadget/udc/trace.h b/drivers/usb/gadget/udc/trace.h
index a5ed26fbc2dad..661158d3a39cd 100644
--- a/drivers/usb/gadget/udc/trace.h
+++ b/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)
-- 
2.51.0