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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Aaron Ma <aaron.ma@canonical.com>,
        Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 4.4 81/86] usb: xhci: fix uninitialized completion when USB3 port got wrong status
Date:   Thu, 29 Nov 2018 15:12:46 +0100
Message-Id: <20181129140116.249572061@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aaron Ma <aaron.ma@canonical.com>

commit 958c0bd86075d4ef1c936998deefe1947e539240 upstream.

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>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-hub.c  |    2 +-
 drivers/usb/host/xhci-ring.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -744,7 +744,7 @@ static u32 xhci_get_port_status(struct u
 			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;
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1673,7 +1673,7 @@ static void handle_port_status(struct xh
 	 * RExit to a disconnect state).  If so, let the the driver know it's
 	 * out of the RExit state.
 	 */
-	if (!DEV_SUPERSPEED_ANY(temp) &&
+	if (!DEV_SUPERSPEED_ANY(temp) && hcd->speed < HCD_USB3 &&
 			test_and_clear_bit(faked_port_index,
 				&bus_state->rexit_ports)) {
 		complete(&bus_state->rexit_done[faked_port_index]);