usb: dwc3: gadget: free trb pool only from epnum 2

commit 5bf8fae33d14cc5c3c53a926f9079f92c8b082b0 upstream.

we never allocate a TRB pool for physical endpoints
0 and 1 so trying to free it (a invalid TRB pool pointer)
will lead us in a warning while removing dwc3.ko module.

In order to fix the situation, all we have to do is skip
dwc3_free_trb_pool() for physical endpoints 0 and 1 just
as we while deleting endpoints from the endpoints list.

Signed-off-by: George Cherian <george.cherian@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 80e3094..8ed83b9 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1483,10 +1483,19 @@ static void dwc3_gadget_free_endpoints(struct dwc3 *dwc)
 
        for (epnum = 0; epnum < DWC3_ENDPOINTS_NUM; epnum++) {
                dep = dwc->eps[epnum];
-               dwc3_free_trb_pool(dep);
-
-               if (epnum != 0 && epnum != 1)
+               /*
+                * Physical endpoints 0 and 1 are special; they form the
+                * bi-directional USB endpoint 0.
+                *
+                * For those two physical endpoints, we don't allocate a TRB
+                * pool nor do we add them the endpoints list. Due to that, we
+                * shouldn't do these two operations otherwise we would end up
+                * with all sorts of bugs when removing dwc3.ko.
+                */
+               if (epnum != 0 && epnum != 1) {
+                       dwc3_free_trb_pool(dep);
                        list_del(&dep->endpoint.ep_list);
+               }
 
                kfree(dep);
        }