[PATCH 4.8 129/138] usb: chipidea: host: fix NULL ptr dereference during shutdown

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Stefan Wahren <stefan.wahren@xxxxxxxx>

commit 991d5add50a5bb6ab8f12f2129f5c7487f6baaf6 upstream.

After commit b09b5224fe86 ("usb: chipidea: implement platform shutdown
callback") and commit 43a404577a93 ("usb: chipidea: host: set host to
be null after hcd is freed") a NULL pointer dereference is caused
on i.MX23 during shutdown. So ensure that role is set to CI_ROLE_END and
we finish interrupt handling before the hcd is deallocated. This avoids
the NULL pointer dereference.

Suggested-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stefan Wahren <stefan.wahren@xxxxxxxx>
Fixes: b09b5224fe86 ("usb: chipidea: implement platform shutdown callback")
Signed-off-by: Peter Chen <peter.chen@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/usb/chipidea/host.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/usb/chipidea/host.c
+++ b/drivers/usb/chipidea/host.c
@@ -185,6 +185,8 @@ static void host_stop(struct ci_hdrc *ci
 
 	if (hcd) {
 		usb_remove_hcd(hcd);
+		ci->role = CI_ROLE_END;
+		synchronize_irq(ci->irq);
 		usb_put_hcd(hcd);
 		if (ci->platdata->reg_vbus && !ci_otg_is_fsm_mode(ci) &&
 			(ci->platdata->flags & CI_HDRC_TURN_VBUS_EARLY_ON))