syzbot

------------[ 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#0: ksoftirqd/0/15
Modules linked in:
CPU: 0 UID: 0 PID: 15 Comm: ksoftirqd/0 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
RIP: 0010:inet_sock_destruct+0x653/0x800 net/ipv4/af_inet.c:162
Code: 18 4c ff e9 06 fd ff ff e8 fa 73 d3 f7 90 0f 0b 90 e9 35 fe ff ff e8 ec 73 d3 f7 90 0f 0b 90 e9 c5 fe ff ff e8 de 73 d3 f7 90 <0f> 0b 90 e9 04 ff ff ff e8 d0 73 d3 f7 90 0f 0b 90 e9 65 fe ff ff
RSP: 0018:ffffc90000127bb0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888032596e80 RCX: ffffffff8a365bc7
RDX: ffff88801eae2540 RSI: ffffffff8a365cc2 RDI: ffff88801eae2540
RBP: 0000000000000f70 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000f70 R11: 000000000000758b R12: ffff888032596e80
R13: ffff888032596f10 R14: ffffffff81ef102d R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8880d5dec000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f08dd073780 CR3: 000000003e9ba000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 __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
 run_ksoftirqd kernel/softirq.c:1076 [inline]
 run_ksoftirqd+0x38/0x60 kernel/softirq.c:1068
 smpboot_thread_fn+0x3d3/0xaa0 kernel/smpboot.c:160
 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>