BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
IP: kernel_sock_shutdown+0x4a/0xc0 net/socket.c:3255
PGD 8000000147e7f067 P4D 8000000147e7f067 PUD 1abb62067 PMD 0 
Oops: 0000 [#1] SMP PTI
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 16080 Comm: syz-executor1 Not tainted 4.16.0+ #87
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:kernel_sock_shutdown+0x4a/0xc0 net/socket.c:3255
RSP: 0018:ffff88016728fd20 EFLAGS: 00010246
RAX: ffffffff87b2a5fd RBX: ffff88014bfa6198 RCX: 0000000000040000
RDX: ffffc90001f9c000 RSI: 0000000000000090 RDI: 0000000000000091
RBP: ffff88016728fd60 R08: 0000000001080020 R09: 0000000000000002
R10: ffffffff7fffffff R11: 0000000000100000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000028 R15: 0000000000000000
FS:  00007f14bb723700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000028 CR3: 000000014af34000 CR4: 00000000001406f0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 smc_shutdown+0x674/0x810 net/smc/af_smc.c:1264
 SYSC_shutdown+0x2a3/0x400 net/socket.c:1901
 SyS_shutdown+0x44/0x60 net/socket.c:1892
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x455979
RSP: 002b:00007f14bb722c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
RAX: ffffffffffffffda RBX: 00007f14bb7236d4 RCX: 0000000000455979
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000065c R14: 00000000006fd940 R15: 0000000000000000
Code: 8b 40 08 89 45 d0 8b 83 90 0c 00 00 89 45 d4 4c 8b 23 44 8b bb 88 0c 00 00 e8 73 7e ae f9 4c 89 75 c0 4d 8d 76 28 4d 85 e4 75 5d <4d> 8b 2e 4c 89 f7 e8 9b f3 05 fa 49 83 c5 60 48 83 38 00 75 52 
RIP: kernel_sock_shutdown+0x4a/0xc0 net/socket.c:3255 RSP: ffff88016728fd20
CR2: 0000000000000028
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