rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10499 ticks this GP) idle=cb2/1/0x4000000000000000 softirq=9978/9987 fqs=0 
	(t=10501 jiffies g=4397 q=138)
rcu: rcu_preempt kthread starved for 10502 jiffies! g4397 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:14232 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3779 [inline]
 __schedule+0x404/0x890 kernel/sched/core.c:4528
 schedule+0x3e/0xf0 kernel/sched/core.c:4606
 schedule_timeout+0x1bd/0x2e0 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline]
 rcu_gp_kthread+0x702/0xc70 kernel/rcu/tree.c:2099
 kthread+0x15a/0x180 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
NMI backtrace for cpu 0
CPU: 0 PID: 7654 Comm: syz-executor.3 Not tainted 5.10.0-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+0xa9/0xd1 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.8+0x53/0x6c lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0xe0/0x100 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:39
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0xac/0xdc kernel/rcu/tree_stall.h:331
 print_cpu_stall kernel/rcu/tree_stall.h:563 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:637 [inline]
 rcu_pending kernel/rcu/tree.c:3694 [inline]
 rcu_sched_clock_irq.cold.94+0x6a/0x635 kernel/rcu/tree.c:2567
 update_process_times+0x54/0x90 kernel/time/timer.c:1709
 tick_sched_handle.isra.24+0x20/0x60 kernel/time/tick-sched.c:176
 tick_sched_timer+0x74/0x90 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x1e1/0x4f0 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xfc/0x210 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x93/0x2a0 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0xd5/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x33/0x60 kernel/locking/spinlock.c:199
Code: 83 c7 18 48 8b 75 08 e8 9b 53 12 fe 48 89 df e8 83 99 12 fe e8 7e c5 1c fe 48 83 3d ee d6 19 01 00 74 1f fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 53 df 0e fe 65 8b 05 bc d1 ef 7c 85 c0 74 05 5b
RSP: 0018:ffffc900049f7b90 EFLAGS: 00000282
RAX: 0000000001d1da8f RBX: ffff888237c2db80 RCX: ffffc900049f7b4c
RDX: 0000000000000000 RSI: ffffffff83f1c073 RDI: ffffffff83f554f6
RBP: ffffc900049f7b98 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 000000000000000a R12: ffff888116c18140
R13: ffff888116c18140 R14: ffff888237c2db98 R15: ffff888237c2db80
 rq_unlock_irq kernel/sched/sched.h:1317 [inline]
 __schedule+0x7ff/0x890 kernel/sched/core.c:4531
 schedule+0x3e/0xf0 kernel/sched/core.c:4606
 tty_open+0x1b9/0x4b0 drivers/tty/tty_io.c:2040
 chrdev_open+0xa0/0x1d0 fs/char_dev.c:414
 do_dentry_open+0x163/0x3d0 fs/open.c:817
 vfs_open+0x28/0x30 fs/open.c:931
 do_open fs/namei.c:3252 [inline]
 path_openat+0x476/0xa90 fs/namei.c:3369
 do_filp_open+0x8e/0x100 fs/namei.c:3396
 do_sys_openat2+0x218/0x2d0 fs/open.c:1168
 do_sys_open+0x48/0x80 fs/open.c:1184
 __do_sys_openat fs/open.c:1200 [inline]
 __se_sys_openat fs/open.c:1195 [inline]
 __x64_sys_openat+0x1b/0x20 fs/open.c:1195
 do_syscall_64+0x31/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a989
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd6caa98c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a989
RDX: 0000000000000000 RSI: 0000000020000380 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd6caa996d4
R13: 00000000004c86f8 R14: 00000000004dfaa8 R15: 00000000ffffffff