Junxiao Bi [off-list ref] wrote:

The following panic happened when I run ocfs2-test on linux-next. Kernel
config is attached.

[64910.905501] BUG: unable to handle kernel NULL pointer dereference at
          (null)
[64910.906466] IP: [<ffffffff8183cc8d>] nf_ct_frag6_gather+0x7ad/0x9c0

[..]

ocfs2_stack_o2cb(O) ocfs2_dlm(O) ocfs2_nodemanager(O) ocfs2_stackglue(O)
iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi xen_kbdfront
xen_netfront xen_fbfront xen_blkfront [last unloaded: ocfs2_stackglue]
[64910.906466] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           O
4.4.0-rc5-next-20151217 #1

Seems like this snapshot still lacks

e97ac12859dbf4d3ee0eddb9798867541d1d1e1e
("netfilter: ipv6: nf_defrag: fix NULL deref panic"),
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/net/ipv6/netfilter/nf_conntrack_reasm.c?id=e97ac12859dbf4d3ee0eddb9798867541d1d1e1e

Its included starting with next-20151221.

Please report back if it occurs with above commit present.

Thanks.