[PATCH 1/2] usb: xhci: fix uninitialized completion when USB3 port got wrong status

[Aaron Ma]

Realtek USB3.0 Card Reader [0bda:0328] reports wrong port status on
Cannon lake PCH USB3.1 xHCI [8086:a36d] after resume from S3,
after clear port reset it works fine.

Since this device is registered on USB3 roothub at boot,
when port status reports not superspeed, xhci_get_port_status will call
an uninitialized completion in bus_state[0].
Kernel will hang because of NULL pointer.

Restrict the USB2 resume status check in USB2 roothub to fix hang issue.
No harm to initialize USB3 bus_state[0] in case it is called.

Signed-off-by: Aaron Ma <aaron.ma@xxxxxxxxxxxxx>
---
 drivers/usb/host/xhci-hub.c  | 2 +-
 drivers/usb/host/xhci-mem.c  | 1 +
 drivers/usb/host/xhci-ring.c | 2 +-
 3 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 7e2a531ba321..d30ca6ceffc9 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -876,7 +876,7 @@ static u32 xhci_get_port_status(struct usb_hcd *hcd,
 			status |= USB_PORT_STAT_SUSPEND;
 	}
 	if ((raw_port_status & PORT_PLS_MASK) == XDEV_RESUME &&
-		!DEV_SUPERSPEED_ANY(raw_port_status)) {
+		!DEV_SUPERSPEED_ANY(raw_port_status) && 1 == hcd_index(hcd)) {
 		if ((raw_port_status & PORT_RESET) ||
 				!(raw_port_status & PORT_PE))
 			return 0xffffffff;
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index b1f27aa38b10..dd2ad50c5289 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -2539,6 +2539,7 @@ int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
 		xhci->bus_state[0].resume_done[i] = 0;
 		xhci->bus_state[1].resume_done[i] = 0;
 		/* Only the USB 2.0 completions will ever be used. */
+		init_completion(&xhci->bus_state[0].rexit_done[i]);
 		init_completion(&xhci->bus_state[1].rexit_done[i]);
 	}
 
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f0a99aa0ac58..894d4625b8b9 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1634,7 +1634,7 @@ static void handle_port_status(struct xhci_hcd *xhci,
 	 * RExit to a disconnect state).  If so, let the the driver know it's
 	 * out of the RExit state.
 	 */
-	if (!DEV_SUPERSPEED_ANY(portsc) &&
+	if (!DEV_SUPERSPEED_ANY(portsc) && 1 == hcd_index(hcd) &&
 			test_and_clear_bit(hcd_portnum,
 				&bus_state->rexit_ports)) {
 		complete(&bus_state->rexit_done[hcd_portnum]);
-- 
2.19.1