usb: xhci: Fix a potential NULL pointer dereference

This patch fixes a potential NULL pointer dereference arising on
non-present/non-initialized xHCI controllers and adds some error
handling to xHCI code

Signed-off-by: Sergey Temerkhanov <s.temerkhanov@gmail.com>
Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@cavium.com>

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 0b09643e09ea3ee0965e2982be91d15d4d11d640..307e1a6f6101410047abafc64f86f0ea35053ba4 100644 (file)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -199,7 +199,7 @@ int xhci_reset(struct xhci_hcor *hcor)
        int ret;
 
        /* Halting the Host first */
-       debug("// Halt the HC\n");
+       debug("// Halt the HC: %p\n", hcor);
        state = xhci_readl(&hcor->or_usbsts) & STS_HALT;
        if (!state) {
                cmd = xhci_readl(&hcor->or_usbcmd);
@@ -1064,6 +1064,8 @@ int usb_lowlevel_init(int index, enum usb_init_type init, void **controller)
        struct xhci_ctrl *ctrl;
        int ret;
 
+       *controller = NULL;
+
        if (xhci_hcd_init(index, &hccr, (struct xhci_hcor **)&hcor) != 0)
                return -ENODEV;
 
@@ -1077,7 +1079,12 @@ int usb_lowlevel_init(int index, enum usb_init_type init, void **controller)
 
        ret = xhci_lowlevel_init(ctrl);
 
-       *controller = &xhcic[index];
+       if (ret) {
+               ctrl->hccr = NULL;
+               ctrl->hcor = NULL;
+       } else {
+               *controller = &xhcic[index];
+       }
 
        return ret;
 }
@@ -1093,9 +1100,11 @@ int usb_lowlevel_stop(int index)
 {
        struct xhci_ctrl *ctrl = (xhcic + index);
 
-       xhci_lowlevel_stop(ctrl);
-       xhci_hcd_stop(index);
-       xhci_cleanup(ctrl);
+       if (ctrl->hcor) {
+               xhci_lowlevel_stop(ctrl);
+               xhci_hcd_stop(index);
+               xhci_cleanup(ctrl);
+       }
 
        return 0;
 }