BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
PGD 80000001ad1fa067 P4D 80000001ad1fa067 PUD 1a6bb9067 PMD 0 
Oops: 0000 [#1] SMP PTI
CPU: 1 PID: 32742 Comm: syz-executor0 Not tainted 4.18.0-rc4+ #27
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:slab_equal_or_root mm/slab.h:228 [inline]
RIP: 0010:cache_from_obj mm/slab.h:374 [inline]
RIP: 0010:kmem_cache_free+0x319/0x2c30 mm/slub.c:2989
Code: 48 f7 d0 48 21 c8 0f 84 6e 01 00 00 49 39 dc 0f 84 7f 01 00 00 44 89 7d 80 49 8d 9c 24 d0 00 00 00 4d 85 f6 0f 85 c6 11 00 00 <4c> 8b 2b 48 89 df e8 3c 81 03 00 48 8b 00 48 0b 45 a0 74 16 4c 89 
RSP: 0018:ffff8800a63ff6f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000d0 RCX: 0000000000000000
RDX: ffffffff8ba11000 RSI: 0000000000000001 RDI: ffffea0006000018
RBP: ffff8800a63ff848 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 000000008010000c R12: 0000000000000000
R13: 000077ff80000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000002274940(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000000000d0 CR3: 000000010f6ac000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 sk_prot_free net/core/sock.c:1516 [inline]
 __sk_destruct+0x8cd/0x9a0 net/core/sock.c:1600
 sk_destruct net/core/sock.c:1608 [inline]
 __sk_free+0x5c4/0x680 net/core/sock.c:1619
 sk_free+0xb4/0x100 net/core/sock.c:1630
 sock_put include/net/sock.h:1667 [inline]
 sctp_close+0xd9a/0xe30 net/sctp/socket.c:1587
 inet_release+0x256/0x2d0 net/ipv4/af_inet.c:427
 inet6_release+0xaf/0x100 net/ipv6/af_inet6.c:459
 __sock_release net/socket.c:599 [inline]
 sock_close+0x11e/0x360 net/socket.c:1150
 __fput+0x458/0xa30 fs/file_table.c:209
 ____fput+0x37/0x40 fs/file_table.c:243
 task_work_run+0x22e/0x2b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:192 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:166 [inline]
 prepare_exit_to_usermode+0x35d/0x430 arch/x86/entry/common.c:197
 syscall_return_slowpath+0x108/0x800 arch/x86/entry/common.c:268
 do_syscall_64+0x1ad/0x230 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x40fb91
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 
RSP: 002b:0000000000a3eab0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000014 RCX: 000000000040fb91
RDX: 0000000000000000 RSI: 0000000000730d38 RDI: 0000000000000013
RBP: 0000000000000013 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000a3e930 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000a3f160 R15: 00000000007034c0
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
CR2: 00000000000000d0
---[ end trace 921b8cf815760f25 ]---
RIP: 0010:slab_equal_or_root mm/slab.h:228 [inline]
RIP: 0010:cache_from_obj mm/slab.h:374 [inline]
RIP: 0010:kmem_cache_free+0x319/0x2c30 mm/slub.c:2989
Code: 48 f7 d0 48 21 c8 0f 84 6e 01 00 00 49 39 dc 0f 84 7f 01 00 00 44 89 7d 80 49 8d 9c 24 d0 00 00 00 4d 85 f6 0f 85 c6 11 00 00 <4c> 8b 2b 48 89 df e8 3c 81 03 00 48 8b 00 48 0b 45 a0 74 16 4c 89 
RSP: 0018:ffff8800a63ff6f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 00000000000000d0 RCX: 0000000000000000
RDX: ffffffff8ba11000 RSI: 0000000000000001 RDI: ffffea0006000018
RBP: ffff8800a63ff848 R08: 0000000000000000 R09: 0000000000000002
R10: 0000000000000000 R11: 000000008010000c R12: 0000000000000000
R13: 000077ff80000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000002274940(0000) GS:ffff88021fd00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
TCP: request_sock_TCPv6: Possible SYN flooding on port 20002. Sending cookies.  Check SNMP counters.
CR2: 00000000000000d0 CR3: 000000010f6ac000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400