1 files changed, 54 insertions, 12 deletions

diff --git a/drivers/char/xillybus/xillyusb.c b/drivers/char/xillybus/xillyusb.c
index 39bcbfd908b4..386531474213 100644
--- a/drivers/char/xillybus/xillyusb.c
+++ b/drivers/char/xillybus/xillyusb.c
@@ -50,6 +50,7 @@ MODULE_LICENSE("GPL v2");
 static const char xillyname[] = "xillyusb";
 
 static unsigned int fifo_buf_order;
+static struct workqueue_struct *wakeup_wq;
 
 #define USB_VENDOR_ID_XILINX		0x03fd
 #define USB_VENDOR_ID_ALTERA		0x09fb
@@ -184,6 +185,14 @@ struct xillyusb_dev {
 	struct mutex process_in_mutex; /* synchronize wakeup_all() */
 };
 
+/*
+ * kref_mutex is used in xillyusb_open() to prevent the xillyusb_dev
+ * struct from being freed during the gap between being found by
+ * xillybus_find_inode() and having its reference count incremented.
+ */
+
+static DEFINE_MUTEX(kref_mutex);
+
 /* FPGA to host opcodes */
 enum {
 	OPCODE_DATA = 0,
@@ -561,10 +570,6 @@ static void cleanup_dev(struct kref *kref)
  * errors if executed. The mechanism relies on that xdev->error is assigned
  * a non-zero value by report_io_error() prior to queueing wakeup_all(),
  * which prevents bulk_in_work() from calling process_bulk_in().
- *
- * The fact that wakeup_all() and bulk_in_work() are queued on the same
- * workqueue makes their concurrent execution very unlikely, however the
- * kernel's API doesn't seem to ensure this strictly.
  */
 
 static void wakeup_all(struct work_struct *work)
@@ -619,7 +624,7 @@ static void report_io_error(struct xillyusb_dev *xdev,
 
 	if (do_once) {
 		kref_get(&xdev->kref); /* xdev is used by work item */
-		queue_work(xdev->workq, &xdev->wakeup_workitem);
+		queue_work(wakeup_wq, &xdev->wakeup_workitem);
 	}
 }
 
@@ -1237,9 +1242,16 @@ static int xillyusb_open(struct inode *inode, struct file *filp)
 	int rc;
 	int index;
 
+	mutex_lock(&kref_mutex);
+
 	rc = xillybus_find_inode(inode, (void **)&xdev, &index);
-	if (rc)
+	if (rc) {
+		mutex_unlock(&kref_mutex);
 		return rc;
+	}
+
+	kref_get(&xdev->kref);
+	mutex_unlock(&kref_mutex);
 
 	chan = &xdev->channels[index];
 	filp->private_data = chan;
@@ -1275,8 +1287,6 @@ static int xillyusb_open(struct inode *inode, struct file *filp)
 	    ((filp->f_mode & FMODE_WRITE) && chan->open_for_write))
 		goto unmutex_fail;
 
-	kref_get(&xdev->kref);
-
 	if (filp->f_mode & FMODE_READ)
 		chan->open_for_read = 1;
 
@@ -1413,6 +1423,7 @@ unopen:
 	return rc;
 
 unmutex_fail:
+	kref_put(&xdev->kref, cleanup_dev);
 	mutex_unlock(&chan->lock);
 	return rc;
 }
@@ -1892,6 +1903,13 @@ static const struct file_operations xillyusb_fops = {
 
 static int xillyusb_setup_base_eps(struct xillyusb_dev *xdev)
 {
+	struct usb_device *udev = xdev->udev;
+
+	/* Verify that device has the two fundamental bulk in/out endpoints */
+	if (usb_pipe_type_check(udev, usb_sndbulkpipe(udev, MSG_EP_NUM)) ||
+	    usb_pipe_type_check(udev, usb_rcvbulkpipe(udev, IN_EP_NUM)))
+		return -ENODEV;
+
 	xdev->msg_ep = endpoint_alloc(xdev, MSG_EP_NUM | USB_DIR_OUT,
 				      bulk_out_work, 1, 2);
 	if (!xdev->msg_ep)
@@ -1921,14 +1939,15 @@ static int setup_channels(struct xillyusb_dev *xdev,
 			  __le16 *chandesc,
 			  int num_channels)
 {
-	struct xillyusb_channel *chan;
+	struct usb_device *udev = xdev->udev;
+	struct xillyusb_channel *chan, *new_channels;
 	int i;
 
 	chan = kcalloc(num_channels, sizeof(*chan), GFP_KERNEL);
 	if (!chan)
 		return -ENOMEM;
 
-	xdev->channels = chan;
+	new_channels = chan;
 
 	for (i = 0; i < num_channels; i++, chan++) {
 		unsigned int in_desc = le16_to_cpu(*chandesc++);
@@ -1957,6 +1976,15 @@ static int setup_channels(struct xillyusb_dev *xdev,
 		 */
 
 		if ((out_desc & 0x80) && i < 14) { /* Entry is valid */
+			if (usb_pipe_type_check(udev,
+						usb_sndbulkpipe(udev, i + 2))) {
+				dev_err(xdev->dev,
+					"Missing BULK OUT endpoint %d\n",
+					i + 2);
+				kfree(new_channels);
+				return -ENODEV;
+			}
+
 			chan->writable = 1;
 			chan->out_synchronous = !!(out_desc & 0x40);
 			chan->out_seekable = !!(out_desc & 0x20);
@@ -1966,6 +1994,7 @@ static int setup_channels(struct xillyusb_dev *xdev,
 		}
 	}
 
+	xdev->channels = new_channels;
 	return 0;
 }
 
@@ -2082,9 +2111,11 @@ static int xillyusb_discovery(struct usb_interface *interface)
 	 * just after responding with the IDT, there is no reason for any
 	 * work item to be running now. To be sure that xdev->channels
 	 * is updated on anything that might run in parallel, flush the
-	 * workqueue, which rarely does anything.
+	 * device's workqueue and the wakeup work item. This rarely
+	 * does anything.
 	 */
 	flush_workqueue(xdev->workq);
+	flush_work(&xdev->wakeup_workitem);
 
 	xdev->num_channels = num_channels;
 
@@ -2132,7 +2163,7 @@ static int xillyusb_probe(struct usb_interface *interface,
 	spin_lock_init(&xdev->error_lock);
 	xdev->in_counter = 0;
 	xdev->in_bytes_left = 0;
-	xdev->workq = alloc_workqueue(xillyname, WQ_HIGHPRI, 0);
+	xdev->workq = alloc_workqueue(xillyname, WQ_HIGHPRI | WQ_UNBOUND, 0);
 
 	if (!xdev->workq) {
 		dev_err(&interface->dev, "Failed to allocate work queue\n");
@@ -2227,7 +2258,9 @@ static void xillyusb_disconnect(struct usb_interface *interface)
 
 	xdev->dev = NULL;
 
+	mutex_lock(&kref_mutex);
 	kref_put(&xdev->kref, cleanup_dev);
+	mutex_unlock(&kref_mutex);
 }
 
 static struct usb_driver xillyusb_driver = {
@@ -2242,6 +2275,10 @@ static int __init xillyusb_init(void)
 {
 	int rc = 0;
 
+	wakeup_wq = alloc_workqueue(xillyname, WQ_UNBOUND, 0);
+	if (!wakeup_wq)
+		return -ENOMEM;
+
 	if (LOG2_INITIAL_FIFO_BUF_SIZE > PAGE_SHIFT)
 		fifo_buf_order = LOG2_INITIAL_FIFO_BUF_SIZE - PAGE_SHIFT;
 	else
@@ -2249,12 +2286,17 @@ static int __init xillyusb_init(void)
 
 	rc = usb_register(&xillyusb_driver);
 
+	if (rc)
+		destroy_workqueue(wakeup_wq);
+
 	return rc;
 }
 
 static void __exit xillyusb_exit(void)
 {
 	usb_deregister(&xillyusb_driver);
+
+	destroy_workqueue(wakeup_wq);
 }
 
 module_init(xillyusb_init);