usb: wusbcore: avoid stack overflow in URB enqueue error path
This patch modifies wa_urb_enqueue to return an error and not call the
urb completion routine if it failed to enqueue the urb because the HWA
device is gone. This prevents a stack overflow due to infinite
submit/complete recursion when unplugging the HWA while connected to a
HID device.
Signed-off-by: Thomas Pugliese <thomas.pugliese@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
index 9dabd89..13faac0 100644
--- a/drivers/usb/wusbcore/wa-xfer.c
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -1052,7 +1052,7 @@
* result never kicks in, the xfer will timeout from the USB code and
* dequeue() will be called.
*/
-static void wa_urb_enqueue_b(struct wa_xfer *xfer)
+static int wa_urb_enqueue_b(struct wa_xfer *xfer)
{
int result;
unsigned long flags;
@@ -1063,18 +1063,22 @@
unsigned done;
result = rpipe_get_by_ep(wa, xfer->ep, urb, xfer->gfp);
- if (result < 0)
+ if (result < 0) {
+ pr_err("%s: error_rpipe_get\n", __func__);
goto error_rpipe_get;
+ }
result = -ENODEV;
/* FIXME: segmentation broken -- kills DWA */
mutex_lock(&wusbhc->mutex); /* get a WUSB dev */
if (urb->dev == NULL) {
mutex_unlock(&wusbhc->mutex);
+ pr_err("%s: error usb dev gone\n", __func__);
goto error_dev_gone;
}
wusb_dev = __wusb_dev_get_by_usb_dev(wusbhc, urb->dev);
if (wusb_dev == NULL) {
mutex_unlock(&wusbhc->mutex);
+ pr_err("%s: error wusb dev gone\n", __func__);
goto error_dev_gone;
}
mutex_unlock(&wusbhc->mutex);
@@ -1082,21 +1086,28 @@
spin_lock_irqsave(&xfer->lock, flags);
xfer->wusb_dev = wusb_dev;
result = urb->status;
- if (urb->status != -EINPROGRESS)
+ if (urb->status != -EINPROGRESS) {
+ pr_err("%s: error_dequeued\n", __func__);
goto error_dequeued;
+ }
result = __wa_xfer_setup(xfer, urb);
- if (result < 0)
+ if (result < 0) {
+ pr_err("%s: error_xfer_setup\n", __func__);
goto error_xfer_setup;
+ }
result = __wa_xfer_submit(xfer);
- if (result < 0)
+ if (result < 0) {
+ pr_err("%s: error_xfer_submit\n", __func__);
goto error_xfer_submit;
+ }
spin_unlock_irqrestore(&xfer->lock, flags);
- return;
+ return 0;
- /* this is basically wa_xfer_completion() broken up wa_xfer_giveback()
- * does a wa_xfer_put() that will call wa_xfer_destroy() and clean
- * upundo setup().
+ /*
+ * this is basically wa_xfer_completion() broken up wa_xfer_giveback()
+ * does a wa_xfer_put() that will call wa_xfer_destroy() and undo
+ * setup().
*/
error_xfer_setup:
error_dequeued:
@@ -1108,8 +1119,7 @@
rpipe_put(xfer->ep->hcpriv);
error_rpipe_get:
xfer->result = result;
- wa_xfer_giveback(xfer);
- return;
+ return result;
error_xfer_submit:
done = __wa_xfer_is_done(xfer);
@@ -1117,6 +1127,8 @@
spin_unlock_irqrestore(&xfer->lock, flags);
if (done)
wa_xfer_completion(xfer);
+ /* return success since the completion routine will run. */
+ return 0;
}
/*
@@ -1150,7 +1162,8 @@
list_del_init(&xfer->list_node);
urb = xfer->urb;
- wa_urb_enqueue_b(xfer);
+ if (wa_urb_enqueue_b(xfer) < 0)
+ wa_xfer_giveback(xfer);
usb_put_urb(urb); /* taken when queuing */
}
}
@@ -1256,7 +1269,19 @@
spin_unlock_irqrestore(&wa->xfer_list_lock, my_flags);
queue_work(wusbd, &wa->xfer_enqueue_work);
} else {
- wa_urb_enqueue_b(xfer);
+ result = wa_urb_enqueue_b(xfer);
+ if (result < 0) {
+ /*
+ * URB submit/enqueue failed. Clean up, return an
+ * error and do not run the callback. This avoids
+ * an infinite submit/complete loop.
+ */
+ dev_err(dev, "%s: URB enqueue failed: %d\n",
+ __func__, result);
+ wa_put(xfer->wa);
+ wa_xfer_put(xfer);
+ return result;
+ }
}
return 0;
