multiple allocations for the same socket
------------[ cut here ]------------
WARNING: CPU: 0 PID: 27034 at net/core/sock_reuseport.c:41 reuseport_alloc+0x306/0x3b0 net/core/sock_reuseport.c:39
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 27034 Comm: syz-executor7 Not tainted 4.14.0-rc5-next-20171018+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x41c kernel/panic.c:183
 __warn+0x1c4/0x1e0 kernel/panic.c:546
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:177
 do_trap_no_signal arch/x86/kernel/traps.c:211 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:260
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:297
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:310
 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905
RIP: 0010:reuseport_alloc+0x306/0x3b0 net/core/sock_reuseport.c:39
RSP: 0018:ffff88004e1e7a40 EFLAGS: 00010282
RAX: 0000000000000028 RBX: ffff88004e920a80 RCX: 0000000000000000
RDX: 0000000000000028 RSI: ffffc9000330a000 RDI: ffffed0009c3cf3c
RBP: ffff88004e1e7b10 R08: 0000000000000001 R09: 0000000000000000
R10: ffff88004e1e78f8 R11: 0000000000000000 R12: 1ffff10009c3cf49
R13: ffff88004e920a80 R14: ffff88004e1e7ae8 R15: ffff88004e920eb8
 __reuseport_attach_prog+0x208/0x280 net/core/filter.c:1251
 sk_reuseport_attach_filter+0x38/0x80 net/core/filter.c:1339
 sock_setsockopt+0x164d/0x1ad0 net/core/sock.c:952
 SYSC_setsockopt net/socket.c:1847 [inline]
 SyS_setsockopt+0x2ff/0x360 net/socket.c:1830
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x447c89
RSP: 002b:00007f7d197c1bd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f7d197c26cc RCX: 0000000000447c89
RDX: 0000000000000033 RSI: 0000000000000001 RDI: 0000000000000014
RBP: 0000000000000082 R08: 0000000000000010 R09: 0000000000000000
R10: 0000000020e9bff0 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000082b0 R14: 00000000006ec350 R15: 00007f7d197c2700
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..