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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, Peter Chen <peter.chen@nxp.com>,
        Jack Pham <jackp@codeaurora.org>,
        Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: [PATCH 4.19 009/110] xhci: handle port status events for removed USB3 hcd
Date:   Thu, 29 Nov 2018 15:11:40 +0100
Message-Id: <20181129135921.619729335@linuxfoundation.org>
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4.19-stable review patch.  If anyone has any objections, please let me know.

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

From: Mathias Nyman <mathias.nyman@linux.intel.com>

commit 1245374e9b8340fc255fd51b2015173a83050d03 upstream.

At xhci removal the USB3 hcd (shared_hcd) is removed before the primary
USB2 hcd. Interrupts for port status changes may still occur for USB3
ports after the shared_hcd is freed, causing  NULL pointer dereference.

Check if xhci->shared_hcd is still valid before handing USB3 port events

Cc: <stable@vger.kernel.org>
Reported-by: Peter Chen <peter.chen@nxp.com>
Tested-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/usb/host/xhci-ring.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1552,6 +1552,13 @@ static void handle_port_status(struct xh
 		goto cleanup;
 	}
 
+	/* We might get interrupts after shared_hcd is removed */
+	if (port->rhub == &xhci->usb3_rhub && xhci->shared_hcd == NULL) {
+		xhci_dbg(xhci, "ignore port event for removed USB3 hcd\n");
+		bogus_port_status = true;
+		goto cleanup;
+	}
+
 	hcd = port->rhub->hcd;
 	bus_state = &xhci->bus_state[hcd_index(hcd)];
 	hcd_portnum = port->hcd_portnum;