[PATCH 4.19 113/125] usb: dwc3: gadget: fix race when disabling ep with cancelled xfers

[Greg Kroah-Hartman]

From: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>

[ Upstream commit d8eca64eec7103ab1fbabc0a187dbf6acfb2af93 ]

When disabling an endpoint which has cancelled requests, we should
make sure to giveback requests that are currently pending in the
cancelled list, otherwise we may fall into a situation where command
completion interrupt fires after endpoint has been disabled, therefore
causing a splat.

Fixes: fec9095bdef4 "usb: dwc3: gadget: remove wait_end_transfer"
Reported-by: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191031090713.1452818-1-felipe.balbi@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/usb/dwc3/gadget.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 54de732550648..8398c33d08e7c 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -698,6 +698,12 @@ static void dwc3_remove_requests(struct dwc3 *dwc, struct dwc3_ep *dep)
 
 		dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
 	}
+
+	while (!list_empty(&dep->cancelled_list)) {
+		req = next_request(&dep->cancelled_list);
+
+		dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
+	}
 }
 
 /**
-- 
2.20.1