multiple allocations for the same socket
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3453 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: 1 PID: 3453 Comm: syzkaller728608 Not tainted 4.14.0-rc4+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 panic+0x1e4/0x417 kernel/panic.c:181
 __warn+0x1c4/0x1d9 kernel/panic.c:542
 report_bug+0x211/0x2d0 lib/bug.c:183
 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178
 do_trap_no_signal arch/x86/kernel/traps.c:212 [inline]
 do_trap+0x260/0x390 arch/x86/kernel/traps.c:261
 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311
 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:ffff8801cc867a40 EFLAGS: 00010282
RAX: 0000000000000028 RBX: ffff8801c0914140 RCX: 0000000000000000
RDX: 0000000000000028 RSI: 1ffff1003990cf08 RDI: ffffed003990cf3c
RBP: ffff8801cc867b10 R08: 0000000000000001 R09: 1ffff1003990ced2
R10: 0000000000000000 R11: fffffbfff0e01464 R12: 1ffff1003990cf49
R13: ffff8801c0914140 R14: ffff8801cc867ae8 R15: ffff8801c09145b8
 __reuseport_attach_prog+0x208/0x280 net/core/filter.c:1251
 sk_reuseport_attach_filter+0x38/0x80 net/core/filter.c:1339
 sock_setsockopt+0x165f/0x1ae0 net/core/sock.c:952
 SYSC_setsockopt net/socket.c:1848 [inline]
 SyS_setsockopt+0x2ff/0x360 net/socket.c:1831
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x445fc9
RSP: 002b:00007fa2345dddc8 EFLAGS: 00000202 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000445fc9
RDX: 0000000000000033 RSI: 0000000000000001 RDI: 000000000000000b
RBP: 0000000000000000 R08: 0000000000000010 R09: 00007fa2345de700
R10: 0000000020e9bff0 R11: 0000000000000202 R12: 0000000000000000
R13: 00007fffc4cec5ef R14: 00007fa2345de9c0 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..