> Disabling nf_nat_h323 and nf_conntrack_h323 avoids crash -
> but video conferencing software is no more usable.
>
> BUG: unable to handle kernel paging request at 00100104
> IP: [<f8214f07>] nf_ct_unlink_expect_report

This must be the same bug fixed in SIP module:
commit 3f509c689a07a4aa989b426893d8491a7ffcc410
netfilter: nf_nat_sip: fix incorrect handling of EBUSY for RTCP expectation

Try attached patch (if this is mangled):

--- a/net/ipv4/netfilter/nf_nat_h323.c
+++ b/net/ipv4/netfilter/nf_nat_h323.c
@@ -229,7 +229,10 @@ static int nat_rtp_rtcp(struct sk_buff *skb,
struct nf_conn *ct,
  ret = nf_ct_expect_related(rtcp_exp);
  if (ret == 0)
  break;
- else if (ret != -EBUSY) {
+ else if (ret == -EBUSY) {
+ nf_ct_unexpect_related(rtp_exp);
+ continue;
+ } else if (ret < 0) {
  nf_ct_unexpect_related(rtp_exp);
  nated_port = 0;
  break;