diff -urN linux-2.4.27/drivers/usb/devices.c linux-2.4.28/drivers/usb/devices.c
--- linux-2.4.27/drivers/usb/devices.c	2002-11-28 15:53:14.000000000 -0800
+++ linux-2.4.28/drivers/usb/devices.c	2004-11-17 03:54:21.802406282 -0800
@@ -387,22 +387,31 @@
 
 	if (start > end)
 		return start;
-		
+
+	/*
+	 * Grab device's exclusive_access mutex to prevent its driver or
+	 * devio from using this device while we are accessing it.
+	 */
+	down (&dev->exclusive_access);
+
 	start = usb_dump_device_descriptor(start, end, &dev->descriptor);
 
 	if (start > end)
-		return start;
-	
+		goto out;
+
 	start = usb_dump_device_strings (start, end, dev);
 	
 	for (i = 0; i < dev->descriptor.bNumConfigurations; i++) {
 		if (start > end)
-			return start;
+			goto out;
 		start = usb_dump_config(dev->speed,
 				start, end, dev->config + i,
 				/* active ? */
 				(dev->config + i) == dev->actconfig);
 	}
+
+out:
+	up (&dev->exclusive_access);
 	return start;
 }
 
@@ -543,9 +552,13 @@
 	
 	/* Now look at all of this device's children. */
 	for (chix = 0; chix < usbdev->maxchild; chix++) {
-		if (usbdev->children[chix]) {
-			ret = usb_device_dump(buffer, nbytes, skip_bytes, file_offset, usbdev->children[chix],
+		struct usb_device *childdev = usbdev->children[chix];
+		if (childdev) {
+			usb_inc_dev_use(childdev);
+			ret = usb_device_dump(buffer, nbytes, skip_bytes,
+					file_offset, childdev,
 					bus, level + 1, chix, ++cnt);
+			usb_dec_dev_use(childdev);
 			if (ret == -EFAULT)
 				return total_written;
 			total_written += ret;
diff -urN linux-2.4.27/drivers/usb/devio.c linux-2.4.28/drivers/usb/devio.c
--- linux-2.4.27/drivers/usb/devio.c	2004-08-07 16:26:05.000000000 -0700
+++ linux-2.4.28/drivers/usb/devio.c	2004-11-17 03:54:21.803406323 -0800
@@ -1158,6 +1158,13 @@
 		up_read(&ps->devsem);
 		return -ENODEV;
 	}
+
+	/*
+	 * grab device's exclusive_access mutex to prevent its driver from
+	 * using this device while it is being accessed by us.
+	 */
+	down(&ps->dev->exclusive_access);
+
 	switch (cmd) {
 	case USBDEVFS_CONTROL:
 		ret = proc_control(ps, (void *)arg);
@@ -1237,6 +1244,7 @@
 		ret = proc_ioctl(ps, (void *) arg);
 		break;
 	}
+	up(&ps->dev->exclusive_access);
 	up_read(&ps->devsem);
 	if (ret >= 0)
 		inode->i_atime = CURRENT_TIME;
diff -urN linux-2.4.27/drivers/usb/storage/transport.c linux-2.4.28/drivers/usb/storage/transport.c
--- linux-2.4.27/drivers/usb/storage/transport.c	2004-02-18 05:36:31.000000000 -0800
+++ linux-2.4.28/drivers/usb/storage/transport.c	2004-11-17 03:54:21.854408420 -0800
@@ -627,8 +627,17 @@
 	int need_auto_sense;
 	int result;
 
+	/*
+	 * Grab device's exclusive_access mutex to prevent libusb/usbfs from
+	 * sending out a command in the middle of ours (if libusb sends a
+	 * get_descriptor or something on pipe 0 after our CBW and before
+	 * our CSW, and then we get a stall, we have trouble).
+	 */
+	down(&(us->pusb_dev->exclusive_access));
+
 	/* send the command to the transport layer */
 	result = us->transport(srb, us);
+	up(&(us->pusb_dev->exclusive_access));
 
 	/* if the command gets aborted by the higher layers, we need to
 	 * short-circuit all other processing
@@ -748,7 +757,9 @@
 		srb->use_sg = 0;
 
 		/* issue the auto-sense command */
+		down(&(us->pusb_dev->exclusive_access));
 		temp_result = us->transport(us->srb, us);
+		up(&(us->pusb_dev->exclusive_access));
 
 		/* let's clean up right away */
 		srb->request_buffer = old_request_buffer;
diff -urN linux-2.4.27/drivers/usb/usb.c linux-2.4.28/drivers/usb/usb.c
--- linux-2.4.27/drivers/usb/usb.c	2004-02-18 05:36:31.000000000 -0800
+++ linux-2.4.28/drivers/usb/usb.c	2004-11-17 03:54:21.917411010 -0800
@@ -989,6 +989,7 @@
 	INIT_LIST_HEAD(&dev->filelist);
 
 	init_MUTEX(&dev->serialize);
+	init_MUTEX(&dev->exclusive_access);
 
 	dev->bus->op->allocate(dev);