WARNING: CPU: 1 PID: 3559 at net/core/sock_reuseport.c:41 reuseport_alloc+0x223/0x290 net/core/sock_reuseport.c:39
multiple allocations for the same socket[   46.398464] Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 3559 Comm: syzkaller873510 Not tainted 4.9.57-g9eaaf14 #69
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801cf2cfa88 ffffffff81d91689 ffffffff83a46b40 ffff8801cf2cfb60
 ffffffff83ee8a00 ffffffff82f94533 0000000000000009 ffff8801cf2cfb50
 ffffffff8142e761 0000000041b58ab3 ffffffff84185ca0 ffffffff8142e5a5
Call Trace:
 [<ffffffff81d91689>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81d91689>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8142e761>] panic+0x1bc/0x3a8 kernel/panic.c:179
 [<ffffffff811321e4>] __warn+0x1c4/0x1e0 kernel/panic.c:542
 [<ffffffff811322c4>] warn_slowpath_fmt+0xc4/0x110 kernel/panic.c:565
 [<ffffffff82f94533>] reuseport_alloc+0x223/0x290 net/core/sock_reuseport.c:39
 [<ffffffff82f8cad1>] __reuseport_attach_prog net/core/filter.c:1212 [inline]
 [<ffffffff82f8cad1>] sk_reuseport_attach_filter+0x1c1/0x2a0 net/core/filter.c:1300
 [<ffffffff82ee3077>] sock_setsockopt+0x5f7/0x18e0 net/core/sock.c:912
 [<ffffffff82ed2296>] SYSC_setsockopt net/socket.c:1767 [inline]
 [<ffffffff82ed2296>] SyS_setsockopt+0x216/0x250 net/socket.c:1750
 [<ffffffff838aa045>] entry_SYSCALL_64_fastpath+0x23/0xc6
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..