usb: musb: host: fix potential NULL pointer dereference

musb_start_urb() doesn't check the pass-in parameter if it is NULL.  But
in musb_bulk_nak_timeout() the parameter passed to musb_start_urb() is
returned from first_qh(), which could be NULL.

So wrap the musb_start_urb() call here with a if condition check to
avoid the potential NULL pointer dereference.

Fixes: f283862f3b5c ("usb: musb: NAK timeout scheme on bulk TX endpoint")
Cc: stable@vger.kernel.org # v3.7+
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 4fa372c845e1529e600d0d8408de7fc3627671b3..e7f99d55922af9c82a19722f83794905879d24fc 100644 (file)
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -990,7 +990,9 @@ static void musb_bulk_nak_timeout(struct musb *musb, struct musb_hw_ep *ep,
                        /* set tx_reinit and schedule the next qh */
                        ep->tx_reinit = 1;
                }
-               musb_start_urb(musb, is_in, next_qh);
+
+               if (next_qh)
+                       musb_start_urb(musb, is_in, next_qh);
        }
 }