------------[ cut here ]------------
sk->sk_forward_alloc
WARNING: net/ipv4/af_inet.c:162 at inet_sock_destruct+0x653/0x800 net/ipv4/af_inet.c:162, CPU#1: kworker/1:3/5869
Modules linked in:
CPU: 1 UID: 0 PID: 5869 Comm: kworker/1:3 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: mld mld_ifc_work
RIP: 0010:inet_sock_destruct+0x653/0x800 net/ipv4/af_inet.c:162
Code: 32 4d ff e9 06 fd ff ff e8 fa 71 fc f7 90 0f 0b 90 e9 35 fe ff ff e8 ec 71 fc f7 90 0f 0b 90 e9 c5 fe ff ff e8 de 71 fc f7 90 <0f> 0b 90 e9 04 ff ff ff e8 d0 71 fc f7 90 0f 0b 90 e9 65 fe ff ff
RSP: 0018:ffffc900006a0db0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88803b299100 RCX: ffffffff8a0cd207
RDX: ffff888024b5ca80 RSI: ffffffff8a0cd302 RDI: ffff888024b5ca80
RBP: 0000000000000f70 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000f70 R11: 000000000000751b R12: ffff88803b299100
R13: ffff88803b299190 R14: ffffffff81ee981d R15: 0000000000000006
FS:  0000000000000000(0000) GS:ffff8880d645f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020479ad6a000 CR3: 000000002ffb8000 CR4: 0000000000352ef0
Call Trace:
 <IRQ>
 __sk_destruct+0x85/0xab0 net/core/sock.c:2357
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x5a2/0x10d0 kernel/rcu/tree.c:2897
 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
 do_softirq kernel/softirq.c:523 [inline]
 do_softirq+0xac/0xe0 kernel/softirq.c:510
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x120 kernel/softirq.c:450
 ipv6_get_lladdr+0x299/0x4f0 net/ipv6/addrconf.c:1944
 mld_newpack.isra.0+0x41d/0xa20 net/ipv6/mcast.c:1789
 add_grhead+0x299/0x340 net/ipv6/mcast.c:1886
 add_grec+0x1380/0x1920 net/ipv6/mcast.c:2025
 mld_send_cr net/ipv6/mcast.c:2148 [inline]
 mld_ifc_work+0x3c5/0xc10 net/ipv6/mcast.c:2693
 process_one_work+0xa23/0x1940 kernel/workqueue.c:3314
 process_scheduled_works kernel/workqueue.c:3397 [inline]
 worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
 kthread+0x370/0x450 kernel/kthread.c:436
 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>