syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (1 GPs behind) idle=356/1/0x4000000000000000 softirq=9141/9150 fqs=9 
	(t=10502 jiffies g=6125 q=697)
rcu: rcu_preempt kthread starved for 10435 jiffies! g6125 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I28928    10      2 0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x7d3/0xc40 kernel/sched/core.c:4178
NMI backtrace for cpu 0
CPU: 0 PID: 7615 Comm: syz-executor986 Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1f0/0x31e lib/dump_stack.c:118
 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x199/0x2a0 kernel/rcu/tree_stall.h:320
 print_cpu_stall kernel/rcu/tree_stall.h:553 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:627 [inline]
 rcu_pending kernel/rcu/tree.c:3489 [inline]
 rcu_sched_clock_irq+0x1928/0x1eb0 kernel/rcu/tree.c:2504
 update_process_times+0x12c/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:176 [inline]
 tick_sched_timer+0x254/0x410 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x42d/0x930 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x373/0xd60 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0xf0/0x260 arch/x86/kernel/apic/apic.c:1097
 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]
 sysvec_apic_timer_interrupt+0xb9/0x130 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596
RIP: 0010:rcu_lock_acquire+0x1a/0x30 include/linux/rcupdate.h:241
Code: 3c 24 e8 49 3c d6 f9 48 8b 14 24 e9 3a fe ff ff e8 eb 3c 97 f9 e8 e6 3c 97 f9 48 c7 c7 90 94 2e 89 31 f6 31 d2 b9 02 00 00 00 <45> 31 c0 45 31 c9 68 25 3f dd 87 e8 06 4c 7c f9 48 83 c4 08 c3 90
RSP: 0018:ffffc90003536fd0 EFLAGS: 00000246
RAX: ffffffff87dd3f2a RBX: ffff8880949f0140 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff892e9490
RBP: 0000000004dad81c R08: dffffc0000000000 R09: fffffbfff12da576
R10: fffffbfff12da576 R11: 0000000000000000 R12: ffff888096d4c000
R13: dffffc0000000000 R14: ffffc9000353702c R15: 0000000004dad81c
 rcu_read_lock include/linux/rcupdate.h:634 [inline]
 tipc_sk_lookup+0x85/0x7c0 net/tipc/socket.c:2970
 tipc_sk_rcv+0x2b8/0x1940 net/tipc/socket.c:2461
 tipc_node_xmit+0x257/0x10d0 net/tipc/node.c:1652
 tipc_node_xmit_skb+0x110/0x150 net/tipc/node.c:1712
 tipc_sk_rcv+0x16f4/0x1940 net/tipc/socket.c:2491
 tipc_node_xmit+0x257/0x10d0 net/tipc/node.c:1652
 tipc_sk_push_backlog net/tipc/socket.c:1303 [inline]
 tipc_sk_filter_connect net/tipc/socket.c:2226 [inline]
 tipc_sk_filter_rcv+0x1660/0x3ca0 net/tipc/socket.c:2335
 tipc_sk_enqueue net/tipc/socket.c:2415 [inline]
 tipc_sk_rcv+0x6e1/0x1940 net/tipc/socket.c:2466
 tipc_node_xmit+0x257/0x10d0 net/tipc/node.c:1652
 tipc_node_xmit_skb net/tipc/node.c:1712 [inline]
 tipc_node_distr_xmit+0x2c7/0x3e0 net/tipc/node.c:1727
 tipc_sk_backlog_rcv+0x12f/0x1b0 net/tipc/socket.c:2383
 sk_backlog_rcv include/net/sock.h:996 [inline]
 __release_sock+0x1b2/0x480 net/core/sock.c:2550
 release_sock+0x5d/0x1c0 net/core/sock.c:3066
 tipc_release+0x1182/0x1440 net/tipc/socket.c:638
 __sock_release net/socket.c:605 [inline]
 sock_close+0xd8/0x260 net/socket.c:1278
 __fput+0x2f0/0x750 fs/file_table.c:281
 task_work_run+0x137/0x1c0 kernel/task_work.c:135
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:216 [inline]
 __prepare_exit_to_usermode+0x14c/0x1e0 arch/x86/entry/common.c:246
 do_syscall_64+0x7f/0xe0 arch/x86/entry/common.c:368
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446b59
Code: Bad RIP value.
RSP: 002b:00007ff651764d88 EFLAGS: 00000246 ORIG_RAX: 0000000000000021
RAX: 0000000000000004 RBX: 00000000006dbc48 RCX: 0000000000446b59
RDX: 0000000000000001 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 00000000006dbc40 R08: 0000000000000001 R09: 0000000000000031
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc4c
R13: 00007ff651764d90 R14: 0000000000000007 R15: 0000000000000000