openvswitch: check for null pointer return from nla_nest_start_noflag
The call to nla_nest_start_noflag can return null in the unlikely
event that nla_put returns -EMSGSIZE. Check for this condition to
avoid a null pointer dereference on pointer nla_reply.
Addresses-Coverity: ("Dereference null return value") Fixes: 966bce7074d4 ("openvswitch: Support conntrack zone limit") Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Yi-Hung Wei <yihung.wei@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>