From 966c587260fc46319330385581cab763efe3f5af Mon Sep 17 00:00:00 2001
From: Xiaoguang Wu <xiaoguang.wu@intel.com>
Date: Tue, 20 Nov 2018 16:14:17 +0800
Subject: [PATCH] DM USB: xHCI: fix potential NULL pointer issue.

During S3 process, the dev in the function pci_xhci_device_doorbell
may be set to NULL when disconnection is detected by DM. This patch
is used to remove this risk.

Tracked-On: #1893
Signed-off-by: Xiaoguang Wu <xiaoguang.wu@intel.com>
Reviewed-by: Liang Yang <liang3.yang@intel.com>
Acked-by: Yu Wang <yu1.wang@intel.com>
---
 devicemodel/hw/pci/xhci.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/devicemodel/hw/pci/xhci.c b/devicemodel/hw/pci/xhci.c
index d82d52ac7..47e72bcf2 100644
--- a/devicemodel/hw/pci/xhci.c
+++ b/devicemodel/hw/pci/xhci.c
@@ -2937,6 +2937,9 @@ pci_xhci_device_doorbell(struct pci_xhci_vdev *xdev,
 	}
 
 	dev = XHCI_SLOTDEV_PTR(xdev, slot);
+	if (!dev)
+		return;
+
 	devep = &dev->eps[epid];
 	dev_ctx = pci_xhci_get_dev_ctx(xdev, slot);
 	if (!dev_ctx)