rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-....: (1 GPs behind) idle=3ae/1/0x4000000000000000 softirq=76856/76861 fqs=5232 
	(t=10502 jiffies g=152633 q=1136)
NMI backtrace for cpu 1
CPU: 1 PID: 16178 Comm: syz-executor.4 Not tainted 5.8.0-rc5-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+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x194/0x1cf 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.cold+0x5b3/0xccc kernel/rcu/tree.c:2504
 update_process_times+0x25/0x60 kernel/time/timer.c:1726
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:176
 tick_sched_timer+0x108/0x290 kernel/time/tick-sched.c:1320
 __run_hrtimer kernel/time/hrtimer.c:1520 [inline]
 __hrtimer_run_queues+0x1d5/0xfc0 kernel/time/hrtimer.c:1584
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1646
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x142/0x5e0 arch/x86/kernel/apic/apic.c:1097
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline]
 sysvec_apic_timer_interrupt+0x4f/0x120 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x8c/0xe0 kernel/locking/spinlock.c:191
Code: 48 c7 c0 80 e0 b4 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 37 48 83 3d 3b 96 cc 01 00 74 22 48 89 df 57 9d <0f> 1f 44 00 00 bf 01 00 00 00 e8 35 28 67 f9 65 8b 05 5e b4 19 78
RSP: 0000:ffffc90000da8c50 EFLAGS: 00000282
RAX: 1ffffffff1369c10 RBX: 0000000000000282 RCX: 0000000000000002
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000282
RBP: ffff8880ae7255c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880ae7255c0
R13: 00000001000188f9 R14: 00000001000188fe R15: 0000000000000000
 __mod_timer+0x669/0xf40 kernel/time/timer.c:1057
 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:587
RIP: 0010:__sanitizer_cov_trace_const_cmp8+0xa/0x20 kernel/kcov.c:291
Code: 48 8b 0c 24 89 f2 89 fe bf 05 00 00 00 e9 ae fe ff ff 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 48 89 f2 48 89 fe <bf> 07 00 00 00 e9 8c fe ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00
RSP: 0000:ffffc90016297798 EFLAGS: 00000246
RAX: ffffea00021d7088 RBX: 0000000000000000 RCX: ffffffff81a2f9fa
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffea00021d70c0 R08: 0000000000000000 R09: ffffea00021d70c7
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea00021d70c8
R13: ffffea00021d70c0 R14: dffffc0000000000 R15: 00000000004d7000
 compound_head include/linux/page-flags.h:184 [inline]
 PageSwapBacked include/linux/page-flags.h:348 [inline]
 mm_counter_file include/linux/mm.h:1884 [inline]
 mm_counter include/linux/mm.h:1893 [inline]
 zap_pte_range mm/memory.c:1088 [inline]
 zap_pmd_range mm/memory.c:1193 [inline]
 zap_pud_range mm/memory.c:1222 [inline]
 zap_p4d_range mm/memory.c:1243 [inline]
 unmap_page_range+0xe4a/0x2940 mm/memory.c:1264
 unmap_single_vma+0x198/0x300 mm/memory.c:1309
 unmap_vmas+0x16f/0x2f0 mm/memory.c:1341
 exit_mmap+0x2b1/0x510 mm/mmap.c:3150
 __mmput+0x122/0x470 kernel/fork.c:1093
 mmput+0x53/0x60 kernel/fork.c:1114
 exit_mm kernel/exit.c:482 [inline]
 do_exit+0xa8f/0x2a40 kernel/exit.c:792
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline]
 __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:269
 prepare_exit_to_usermode+0x5/0x30 arch/x86/entry/common.c:300
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587
RIP: 0033:0x411b77
Code: Bad RIP value.
RSP: 002b:0000000000c9fb20 EFLAGS: 00000202
RAX: 00000000719068fe RBX: 000000006091d675 RCX: 0000001b2d320000
RDX: 00000000719068fe RSI: 00000000000008fe RDI: ffffffff719068fe
RBP: 000000000000000f R08: 00000000719068fe R09: 0000000071906902
R10: 0000000000c9fcd0 R11: 0000000000000246 R12: 000000000078bf88
R13: 0000000080000000 R14: 00007f63dbe02008 R15: 0000000000000027