Check that array index is in-bounds before accessing the synths[] array.
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: stable <stable@vger.kernel.org>
Cc: Nickolai Zeldovich <nickolai@csail.mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>