------------[ cut here ]------------
WARNING: CPU: 0 PID: 12 at net/ipv6/route.c:4857 rt6_multipath_rebalance+0x455/0x8b0
Modules linked in:
CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:rt6_multipath_rebalance+0x455/0x8b0
Code: ff ff 44 89 e1 80 e1 07 38 c1 0f 8c 85 fe ff ff 4c 89 e7 e8 bd 1f f2 f7 e9 78 fe ff ff e8 73 b4 8e f7 eb 05 e8 6c b4 8e f7 90 <0f> 0b 90 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d e9 45 c4 4b 01
RSP: 0018:ffffc900000f6fc0 EFLAGS: 00010293
RAX: ffffffff8a30f6bd RBX: dffffc0000000000 RCX: ffff88801c2e5640
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff5200001edf0 R12: ffff88810a4158de
R13: ffff88810a415890 R14: 0000000000000000 R15: 1ffff11021482b12
FS:  0000000000000000(0000) GS:ffff8880b8618000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b3211bff8 CR3: 0000000011382000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 fib6_ifdown+0x401/0x4c0
 fib6_clean_node+0x24d/0x590
 fib6_walk_continue+0x67b/0x910
 fib6_walk+0x149/0x290
 __fib6_clean_all+0x234/0x380
 rt6_disable_ip+0x120/0x720
 addrconf_ifdown+0x15d/0x1880
 addrconf_notify+0x1bc/0x1010
 notifier_call_chain+0x1b6/0x3e0
 netif_close_many+0x29c/0x410
 unregister_netdevice_many_notify+0x7b9/0x1ff0
 ops_undo_list+0x3dc/0x990
 cleanup_net+0x4c5/0x800
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>
