USB: xhci: Fail gracefully if there's no SS ep companion descriptor.

This is a work around for a bug in the SuperSpeed Endpoint Companion Descriptor
parsing code.  It fails in some corner cases, which means ep->ss_ep_comp may be
NULL.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 075e1036bcb4..41aca003ee82 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -496,7 +496,12 @@ int xhci_endpoint_init(struct xhci_hcd *xhci,
                 max_packet = ep->desc.wMaxPacketSize;
                 ep_ctx->ep_info2 |= MAX_PACKET(max_packet);
                 /* dig out max burst from ep companion desc */
-                max_packet = ep->ss_ep_comp->desc.bMaxBurst;
+                if (!ep->ss_ep_comp) {
+                        xhci_warn(xhci, "WARN no SS endpoint companion descriptor.\n");
+                        max_packet = 0;
+                } else {
+                        max_packet = ep->ss_ep_comp->desc.bMaxBurst;
+                }
                 ep_ctx->ep_info2 |= MAX_BURST(max_packet);
                 break;
         case USB_SPEED_HIGH: