diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 44bc27170e8ce..4007cece638b4 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -4726,10 +4726,17 @@ static int get_bMaxPacketSize0(struct usb_device *udev,
  * the port lock.  For a newly detected device that is not accessible
  * through any global pointers, it's not necessary to lock the device,
  * but it is still necessary to lock the port.
+ *
+ * For a newly detected device, @dev_descr must be NULL.  The device
+ * descriptor retrieved from the device will then be stored in
+ * @udev->descriptor.  For an already existing device, @dev_descr
+ * must be non-NULL.  The device descriptor will be stored there,
+ * not in @udev->descriptor, because descriptors for registered
+ * devices are meant to be immutable.
  */
 static int
 hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
-		int retry_counter)
+		int retry_counter, struct usb_device_descriptor *dev_descr)
 {
 	struct usb_device	*hdev = hub->hdev;
 	struct usb_hcd		*hcd = bus_to_hcd(hdev->bus);
@@ -4741,6 +4748,7 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 	int			devnum = udev->devnum;
 	const char		*driver_name;
 	bool			do_new_scheme;
+	const bool		initial = !dev_descr;
 	int			maxp0;
 	struct usb_device_descriptor	*buf, *descr;
 
@@ -4779,32 +4787,34 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 	}
 	oldspeed = udev->speed;
 
-	/* USB 2.0 section 5.5.3 talks about ep0 maxpacket ...
-	 * it's fixed size except for full speed devices.
-	 * For Wireless USB devices, ep0 max packet is always 512 (tho
-	 * reported as 0xff in the device descriptor). WUSB1.0[4.8.1].
-	 */
-	switch (udev->speed) {
-	case USB_SPEED_SUPER_PLUS:
-	case USB_SPEED_SUPER:
-	case USB_SPEED_WIRELESS:	/* fixed at 512 */
-		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512);
-		break;
-	case USB_SPEED_HIGH:		/* fixed at 64 */
-		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
-		break;
-	case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
-		/* to determine the ep0 maxpacket size, try to read
-		 * the device descriptor to get bMaxPacketSize0 and
-		 * then correct our initial guess.
+	if (initial) {
+		/* USB 2.0 section 5.5.3 talks about ep0 maxpacket ...
+		 * it's fixed size except for full speed devices.
+		 * For Wireless USB devices, ep0 max packet is always 512 (tho
+		 * reported as 0xff in the device descriptor). WUSB1.0[4.8.1].
 		 */
-		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
-		break;
-	case USB_SPEED_LOW:		/* fixed at 8 */
-		udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8);
-		break;
-	default:
-		goto fail;
+		switch (udev->speed) {
+		case USB_SPEED_SUPER_PLUS:
+		case USB_SPEED_SUPER:
+		case USB_SPEED_WIRELESS:	/* fixed at 512 */
+			udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512);
+			break;
+		case USB_SPEED_HIGH:		/* fixed at 64 */
+			udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
+			break;
+		case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
+			/* to determine the ep0 maxpacket size, try to read
+			 * the device descriptor to get bMaxPacketSize0 and
+			 * then correct our initial guess.
+			 */
+			udev->ep0.desc.wMaxPacketSize = cpu_to_le16(64);
+			break;
+		case USB_SPEED_LOW:		/* fixed at 8 */
+			udev->ep0.desc.wMaxPacketSize = cpu_to_le16(8);
+			break;
+		default:
+			goto fail;
+		}
 	}
 
 	if (udev->speed == USB_SPEED_WIRELESS)
@@ -4827,22 +4837,24 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 	if (udev->speed < USB_SPEED_SUPER)
 		dev_info(&udev->dev,
 				"%s %s USB device number %d using %s\n",
-				(udev->config) ? "reset" : "new", speed,
+				(initial ? "new" : "reset"), speed,
 				devnum, driver_name);
 
-	/* Set up TT records, if needed  */
-	if (hdev->tt) {
-		udev->tt = hdev->tt;
-		udev->ttport = hdev->ttport;
-	} else if (udev->speed != USB_SPEED_HIGH
-			&& hdev->speed == USB_SPEED_HIGH) {
-		if (!hub->tt.hub) {
-			dev_err(&udev->dev, "parent hub has no TT\n");
-			retval = -EINVAL;
-			goto fail;
+	if (initial) {
+		/* Set up TT records, if needed  */
+		if (hdev->tt) {
+			udev->tt = hdev->tt;
+			udev->ttport = hdev->ttport;
+		} else if (udev->speed != USB_SPEED_HIGH
+				&& hdev->speed == USB_SPEED_HIGH) {
+			if (!hub->tt.hub) {
+				dev_err(&udev->dev, "parent hub has no TT\n");
+				retval = -EINVAL;
+				goto fail;
+			}
+			udev->tt = &hub->tt;
+			udev->ttport = port1;
 		}
-		udev->tt = &hub->tt;
-		udev->ttport = port1;
 	}
 
 	/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way?
@@ -4871,6 +4883,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 
 			maxp0 = get_bMaxPacketSize0(udev, buf,
 					GET_DESCRIPTOR_BUFSIZE, retries == 0);
+			if (maxp0 > 0 && !initial &&
+					maxp0 != udev->descriptor.bMaxPacketSize0) {
+				dev_err(&udev->dev, "device reset changed ep0 maxpacket size!\n");
+				retval = -ENODEV;
+				goto fail;
+			}
 
 			retval = hub_port_reset(hub, port1, udev, delay, false);
 			if (retval < 0)		/* error or disconnect */
@@ -4940,6 +4958,12 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 		} else {
 			u32 delay;
 
+			if (!initial && maxp0 != udev->descriptor.bMaxPacketSize0) {
+				dev_err(&udev->dev, "device reset changed ep0 maxpacket size!\n");
+				retval = -ENODEV;
+				goto fail;
+			}
+
 			delay = udev->parent->hub_delay;
 			udev->hub_delay = min_t(u32, delay,
 						USB_TP_TRANSMISSION_DELAY_MAX);
@@ -4983,7 +5007,10 @@ hub_port_init(struct usb_hub *hub, struct usb_device *udev, int port1,
 					retval);
 		goto fail;
 	}
-	udev->descriptor = *descr;
+	if (initial)
+		udev->descriptor = *descr;
+	else
+		*dev_descr = *descr;
 	kfree(descr);
 
 	/*
@@ -5287,7 +5314,7 @@ static void hub_port_connect(struct usb_hub *hub, int port1, u16 portstatus,
 		}
 
 		/* reset (non-USB 3.0 devices) and get descriptor */
-		status = hub_port_init(hub, udev, port1, i);
+		status = hub_port_init(hub, udev, port1, i, NULL);
 		if (status < 0)
 			goto loop;
 
@@ -5896,7 +5923,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 	struct usb_device		*parent_hdev = udev->parent;
 	struct usb_hub			*parent_hub;
 	struct usb_hcd			*hcd = bus_to_hcd(udev->bus);
-	struct usb_device_descriptor	descriptor = udev->descriptor;
+	struct usb_device_descriptor	descriptor;
 	struct usb_host_bos		*bos;
 	int				i, j, ret = 0;
 	int				port1 = udev->portnum;
@@ -5938,7 +5965,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 		/* ep0 maxpacket size may change; let the HCD know about it.
 		 * Other endpoints will be handled by re-enumeration. */
 		usb_ep0_reinit(udev);
-		ret = hub_port_init(parent_hub, udev, port1, i);
+		ret = hub_port_init(parent_hub, udev, port1, i, &descriptor);
 		if (ret >= 0 || ret == -ENOTCONN || ret == -ENODEV)
 			break;
 	}
@@ -5950,7 +5977,6 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
 	/* Device might have changed firmware (DFU or similar) */
 	if (descriptors_changed(udev, &descriptor, bos)) {
 		dev_info(&udev->dev, "device firmware changed\n");
-		udev->descriptor = descriptor;	/* for disconnect() calls */
 		goto re_enumerate;
 	}
 
