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From:   Aaron Ma <aaron.ma@canonical.com>
To:     aaron.ma@canonical.com, mathias.nyman@intel.com,
        gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/2] usb: xhci: fix uninitialized completion when USB3 port got wrong status
Date:   Tue, 23 Oct 2018 01:42:46 +0800
Message-Id: <1540230167-12528-1-git-send-email-aaron.ma@canonical.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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.

Cc: stable@vger.kernel.org
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
---
 drivers/usb/host/xhci-hub.c  | 2 +-
 drivers/usb/host/xhci-ring.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 7e2a531ba321..56a08daa7431 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) && hcd->speed < HCD_USB3) {
 		if ((raw_port_status & PORT_RESET) ||
 				!(raw_port_status & PORT_PE))
 			return 0xffffffff;
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index f0a99aa0ac58..7318fc422b6c 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) && hcd->speed < HCD_USB3 &&
 			test_and_clear_bit(hcd_portnum,
 				&bus_state->rexit_ports)) {
 		complete(&bus_state->rexit_done[hcd_portnum]);
-- 
2.19.1