From 1c29f4306f557ef5d9ed515ec8881f4d1735b058 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?=
 <emulatorman@parabola.nu>
Date: Tue, 27 Sep 2016 10:34:19 -0300
Subject: Linux-libre 4.7.5-gnu

---
 drivers/usb/chipidea/udc.c | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'drivers/usb/chipidea/udc.c')

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index dfec5a176..b93356834 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -949,6 +949,15 @@ static int isr_setup_status_phase(struct ci_hdrc *ci)
 	int retval;
 	struct ci_hw_ep *hwep;
 
+	/*
+	 * Unexpected USB controller behavior, caused by bad signal integrity
+	 * or ground reference problems, can lead to isr_setup_status_phase
+	 * being called with ci->status equal to NULL.
+	 * If this situation occurs, you should review your USB hardware design.
+	 */
+	if (WARN_ON_ONCE(!ci->status))
+		return -EPIPE;
+
 	hwep = (ci->ep0_dir == TX) ? ci->ep0out : ci->ep0in;
 	ci->status->context = ci;
 	ci->status->complete = isr_setup_status_complete;
-- 
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