audit: type=1400 audit(1573068774.066:15534): avc:  denied  { write } for  pid=17952 comm="syz-executor.0" scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=netlink_generic_socket permissive=1
IPv6: ADDRCONF(NETDEV_CHANGE): lo: link becomes ready
skbuff: skb_over_panic: text:00000000f814cc9b len:56 put:8 head:00000000d02a6f61 data:0000000017d4e053 tail:0xc8 end:0xc0 dev:ip6tnl0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:104!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN NOPTI
Modules linked in:
CPU: 1 PID: 72 Comm: kworker/1:2 Not tainted 4.14.152+ #0
Workqueue: ipv6_addrconf addrconf_dad_work
task: 0000000020c4f73a task.stack: 000000003cfaddcc
RIP: 0010:skb_panic+0x16c/0x16e net/core/skbuff.c:104
RSP: 0018:ffff8881d5837868 EFLAGS: 00010286
RAX: 0000000000000085 RBX: ffff8881c72e8500 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8c46a080 RDI: ffffed103ab06eff
RBP: ffffffff8c689c20 R08: 0000000000000085 R09: ffffed103b764ce9
R10: ffffed103b764ce8 R11: ffff8881dbb26747 R12: ffffffff8bd8480e
R13: 0000000000000008 R14: ffff8881d5899100 R15: 00000000000000c0
FS:  0000000000000000(0000) GS:ffff8881dbb00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020060000 CR3: 0000000125826003 CR4: 00000000001606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 skb_over_panic net/core/skbuff.c:109 [inline]
 skb_put.cold+0x24/0x24 net/core/skbuff.c:1699
 mld_newpack+0x4ce/0x7a0 net/ipv6/mcast.c:1608
 add_grhead.isra.0+0x29c/0x370 net/ipv6/mcast.c:1691
 add_grec+0x6a3/0xf10 net/ipv6/mcast.c:1822
 mld_send_initial_cr.part.0+0xb1/0x140 net/ipv6/mcast.c:2072
 mld_send_initial_cr net/ipv6/mcast.c:2090 [inline]
 ipv6_mc_dad_complete+0x163/0x1b0 net/ipv6/mcast.c:2084
 addrconf_dad_completed+0x7eb/0xad0 net/ipv6/addrconf.c:4079
 addrconf_dad_begin net/ipv6/addrconf.c:3867 [inline]
 addrconf_dad_work+0x99e/0x1170 net/ipv6/addrconf.c:3969
 process_one_work+0x7f1/0x1580 kernel/workqueue.c:2134
 worker_thread+0xdd/0xdf0 kernel/workqueue.c:2271
 kthread+0x31f/0x430 kernel/kthread.c:232
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:404
Code: 20 ff 4c 8b 4c 24 10 8b 4b 78 41 56 45 89 e8 4c 89 e2 41 57 48 89 ee 48 c7 c7 40 96 68 8c ff 74 24 10 ff 74 24 20 e8 39 b7 ee fe <0f> 0b e8 d7 91 fd fe 4c 8b 64 24 18 e8 fd 54 20 ff 48 c7 c1 e0 
RIP: skb_panic+0x16c/0x16e net/core/skbuff.c:104 RSP: ffff8881d5837868
---[ end trace 24b44e339af1a94e ]---
EXT4-fs (loop4): ext4_check_descriptors: Block bitmap for group 0 overlaps superblock