rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 GPs behind) idle=632/1/0x4000000000000000 softirq=77934/77935 fqs=1 
	(detected by 0, t=15605 jiffies, g=131441, q=220)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 146 Comm: kworker/u4:4 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_shutdown_worker
RIP: 0010:unwind_next_frame+0x106/0x1f90 arch/x86/kernel/unwind_orc.c:425
Code: 1e 16 00 00 49 8b 47 48 48 89 44 24 08 49 8d 47 38 48 89 c2 48 89 04 24 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 ff 15 00 00 49 8b 47 38 bf 01 00 00 00 48 89 44 24 10 e8 51
RSP: 0018:ffffc90000da8838 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 1ffff920001b510f RCX: 0000000000000000
RDX: 1ffff920001b5129 RSI: 0000000000000000 RDI: ffffc90000da8910
RBP: 0000000000000001 R08: ffffffff8b18f052 R09: 0000000000000001
R10: 000000000007201e R11: 0000000000000001 R12: ffffc90000da8958
R13: 0000000000000000 R14: ffff8880a8eb40c0 R15: ffffc90000da8910
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004f4bf0 CR3: 000000008fcdd000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_stack_walk+0x81/0xf0 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kmem_cache_free+0x7f/0x310 mm/slab.c:3694
 inet_bind_bucket_destroy net/ipv4/inet_hashtables.c:88 [inline]
 inet_bind_bucket_destroy+0xdf/0x120 net/ipv4/inet_hashtables.c:84
 inet_twsk_bind_unhash+0x121/0x1b0 net/ipv4/inet_timewait_sock.c:39
 inet_twsk_kill+0x21d/0x470 net/ipv4/inet_timewait_sock.c:59
 call_timer_fn+0x1ac/0x760 kernel/time/timer.c:1404
 expire_timers kernel/time/timer.c:1449 [inline]
 __run_timers.part.0+0x54c/0xa20 kernel/time/timer.c:1773
 __run_timers kernel/time/timer.c:1745 [inline]
 run_timer_softirq+0xae/0x1a0 kernel/time/timer.c:1786
 __do_softirq+0x34c/0xa60 kernel/softirq.c:292
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x111/0x170 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:387 [inline]
 __irq_exit_rcu kernel/softirq.c:417 [inline]
 irq_exit_rcu+0x229/0x270 kernel/softirq.c:429
 sysvec_apic_timer_interrupt+0x54/0x120 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596
RIP: 0010:check_kcov_mode kernel/kcov.c:165 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x2a/0x60 kernel/kcov.c:197
Code: 65 48 8b 14 25 00 ff 01 00 65 8b 05 90 47 8e 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 35 8b 82 04 14 00 00 85 c0 74 2b <8b> 82 e0 13 00 00 83 f8 02 75 20 48 8b 8a e8 13 00 00 8b 92 e4 13
RSP: 0018:ffffc900014b73a8 EFLAGS: 00000246
RAX: 0000000080000000 RBX: ffff88809285ba00 RCX: ffffffff866cdff9
RDX: ffff8880a8eb40c0 RSI: ffffffff866cdf14 RDI: 0000000000000004
RBP: 0000000000000005 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000009 R11: 0000000000000000 R12: 0000000000000009
R13: ffff88805f835160 R14: ffffc900014b7450 R15: dffffc0000000000
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x74/0x1e0 net/netfilter/core.c:512
 nf_hook_state_init include/linux/netfilter.h:153 [inline]
 nf_hook+0x38f/0x620 include/linux/netfilter.h:259
 NF_HOOK include/linux/netfilter.h:305 [inline]
 ip6_xmit+0xdd2/0x1e80 net/ipv6/ip6_output.c:280
 inet6_csk_xmit+0x339/0x610 net/ipv6/inet6_connection_sock.c:135
 __tcp_transmit_skb+0x1884/0x3690 net/ipv4/tcp_output.c:1238
 tcp_transmit_skb net/ipv4/tcp_output.c:1254 [inline]
 tcp_write_xmit+0xebf/0x5c70 net/ipv4/tcp_output.c:2517
 __tcp_push_pending_frames+0xaa/0x330 net/ipv4/tcp_output.c:2692
 tcp_send_fin+0x117/0xbb0 net/ipv4/tcp_output.c:3249
 tcp_close+0xb31/0x11f0 net/ipv4/tcp.c:2492
 inet_release+0xe4/0x1f0 net/ipv4/af_inet.c:428
 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:475
 __sock_release net/socket.c:605 [inline]
 sock_release+0x87/0x1b0 net/socket.c:625
 rds_tcp_conn_path_shutdown+0x1e5/0x3f0 net/rds/tcp_connect.c:216
 rds_conn_shutdown+0x23e/0x904 net/rds/connection.c:386
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
rcu: rcu_preempt kthread starved for 15603 jiffies! g131441 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29120    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178
 schedule+0xd0/0x2a0 kernel/sched/core.c:4253
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1897
 rcu_gp_fqs_loop kernel/rcu/tree.c:1874 [inline]
 rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2044
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293