Merge tag 'usb-ci-v4.8-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/peter...

Peter writes:

Fix the possible kernel panic when the hardware signal is bad for chipidea udc.

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index dfec5a1..b933568 100644 (file)
--- 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;