rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10500 ticks this GP) idle=6ea/1/0x4000000000000002 softirq=15698/15698 fqs=36 
	(t=10500 jiffies g=7093 q=492)
rcu: rcu_preempt kthread starved for 10428 jiffies! g7093 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    29368    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3385 [inline]
 __schedule+0x8a9/0x1970 kernel/sched/core.c:4081
 schedule+0xc3/0x2b0 kernel/sched/core.c:4155
 schedule_timeout+0x38b/0xad0 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline]
 rcu_gp_kthread+0x997/0x1820 kernel/rcu/tree.c:1821
 kthread+0x331/0x3f0 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 8397 Comm: syz-executor.3 Not tainted 5.5.0-rc7-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+0x12d/0x187 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.7+0x4b/0x84 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x18b/0x1b7 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x16f/0x1bc kernel/rcu/tree_stall.h:254
 print_cpu_stall kernel/rcu/tree_stall.h:455 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:529 [inline]
 rcu_pending kernel/rcu/tree.c:2827 [inline]
 rcu_sched_clock_irq.cold.89+0x508/0xc5e kernel/rcu/tree.c:2271
 update_process_times+0x23/0x50 kernel/time/timer.c:1726
 tick_sched_handle+0x77/0x140 kernel/time/tick-sched.c:171
 tick_sched_timer+0x43/0x100 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x32f/0xb50 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x2df/0x760 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline]
 smp_apic_timer_interrupt+0x163/0x5f0 arch/x86/kernel/apic/apic.c:1135
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x51/0x80 kernel/locking/spinlock.c:199
Code: d2 88 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 75 32 48 83 3d 80 28 a1 01 00 74 1f fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 d5 fa 16 fa 65 8b 05 06 6b d0 78 85 c0 74 05 5b
RSP: 0000:ffffc90002b07cc0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: ffff88809a1faa40 RCX: 0000000000000000
RDX: 1ffffffff11a5b7d RSI: 0000000000000006 RDI: ffffffff88d2dbe8
RBP: ffffc90002b07cc8 R08: 0000000000000006 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000b
R13: 000000000000000a R14: dffffc0000000000 R15: 0000000000000001
 spin_unlock_irq include/linux/spinlock.h:388 [inline]
 get_signal+0x147b/0x1d40 kernel/signal.c:2737
 do_signal+0x87/0x1710 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x114/0x2e0 arch/x86/entry/common.c:160
 prepare_exit_to_usermode+0x240/0x2b0 arch/x86/entry/common.c:195
 ret_from_intr+0x26/0x36
RIP: 0033:0x4057e9
Code: d0 ff ff ff 01 48 8b 7c 24 28 c7 44 24 34 00 00 00 00 e8 4a d3 01 00 85 c0 75 23 48 6b 44 24 20 18 8b 7c 24 1c 48 03 44 24 38 <48> 8b 48 10 48 8b 50 08 48 8b 30 e8 e7 ee 00 00 89 44 24 34 64 f0
RSP: 002b:00007f88d86daa70 EFLAGS: 00010206
RAX: 000000002904a1a0 RBX: 0000000000000007 RCX: 0000000000414717
RDX: 9c3772bae5f90c1d RSI: 0000000000000000 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 00007f88d86daa70 R09: 000000000075bf20
R10: 0000000000000000 R11: 0000000000000000 R12: 00007f88d86db6d4
R13: 00000000004cae58 R14: 00000000004e4478 R15: 00000000ffffffff