commit 0e8f0d67401589a141950856902c7d0ec8d9c985 upstream.
... and actually should just check it's given an iovec-backed iterator
in the first place.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>