syzbot

rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-....: (1 GPs behind) idle=142/1/0x4000000000000004 softirq=378875/378876 fqs=5245 
rcu: 	 (t=10501 jiffies g=354313 q=188293)
NMI backtrace for cpu 0
CPU: 0 PID: 30721 Comm: syz-executor.4 Not tainted 4.19.113-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+0x188/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x170/0x1bb kernel/rcu/tree.c:1340
 print_cpu_stall kernel/rcu/tree.c:1478 [inline]
 check_cpu_stall kernel/rcu/tree.c:1550 [inline]
 __rcu_pending kernel/rcu/tree.c:3293 [inline]
 rcu_pending kernel/rcu/tree.c:3336 [inline]
 rcu_check_callbacks.cold+0x634/0xddc kernel/rcu/tree.c:2682
 update_process_times+0x2a/0x70 kernel/time/timer.c:1638
 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:168
 tick_sched_timer+0x42/0x130 kernel/time/tick-sched.c:1278
 __run_hrtimer kernel/time/hrtimer.c:1401 [inline]
 __hrtimer_run_queues+0x2fc/0xd50 kernel/time/hrtimer.c:1463
 hrtimer_interrupt+0x312/0x770 kernel/time/hrtimer.c:1521
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1067 [inline]
 smp_apic_timer_interrupt+0x10c/0x550 arch/x86/kernel/apic/apic.c:1092
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline]
RIP: 0010:kmem_cache_free+0xa4/0x260 mm/slab.c:3766
Code: e8 31 2f 00 00 84 c0 74 76 41 f7 c4 00 02 00 00 74 4e e8 3f 7d cf ff 48 83 3d ff 1d 15 07 00 0f 84 a8 01 00 00 4c 89 e7 57 9d <0f> 1f 44 00 00 4c 8b 64 24 20 0f 1f 44 00 00 65 8b 05 86 48 64 7e
RSP: 0018:ffff8880ae607df0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: ffff888049249000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88803fa58e00 RDI: 0000000000000286
RBP: ffff88812c290080 R08: ffff88803fa58580 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000286
R13: ffffffff8156504d R14: ffff8880ae607e90 R15: dffffc0000000000
 __rcu_reclaim kernel/rcu/rcu.h:236 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0xb2d/0x17f0 kernel/rcu/tree.c:2881
 __do_softirq+0x26c/0x93c kernel/softirq.c:292
 invoke_softirq kernel/softirq.c:372 [inline]
 irq_exit+0x17b/0x1c0 kernel/softirq.c:412
 exiting_irq arch/x86/include/asm/apic.h:544 [inline]
 smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1094
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:893
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x50/0x80 kernel/locking/spinlock.c:192
Code: c0 98 56 b2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 31 48 83 3d e1 91 92 01 00 74 25 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 46 d6 26 fa 65 8b 05 ff 28 e2 78 85 c0 74 02 5d
RSP: 0018:ffff88804260f708 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff1164ad3 RBX: ffff88803fa58580 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffff88803fa58dfc
RBP: ffff8880ae62c280 R08: ffff88803fa58580 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae62c280
R13: ffff88809e22a0c0 R14: ffff88809c680840 R15: 0000000000000402
 finish_lock_switch kernel/sched/core.c:2576 [inline]
 finish_task_switch+0x146/0x780 kernel/sched/core.c:2676
 context_switch kernel/sched/core.c:2829 [inline]
 __schedule+0x86e/0x1d80 kernel/sched/core.c:3515
 preempt_schedule_irq+0xb0/0x140 kernel/sched/core.c:3742
 retint_kernel+0x1b/0x2d
RIP: 0010:unmap_vmas+0xc2/0x180 mm/memory.c:1585
Code: 4c 89 f7 4c 89 e1 4c 89 ea 48 89 de e8 a7 f7 ff ff 48 8d 7b 10 48 89 f8 48 c1 e8 03 80 3c 28 00 0f 85 9a 00 00 00 48 8b 5b 10 <48> 85 db 74 25 e8 f4 0d d7 ff 48 89 d8 48 c1 e8 03 80 3c 28 00 75
RSP: 0018:ffff88804260f920 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: 1ffff11012138d75 RBX: ffff8880a55b5840 RCX: 1ffff110084c1f07
RDX: 0000000000000000 RSI: ffffffff81909489 RDI: ffff8880909c6ba8
RBP: dffffc0000000000 R08: ffff88803fa58580 R09: ffffed101510be9b
R10: ffffed101510be9a R11: ffff8880a885f4d3 R12: ffffffffffffffff
R13: 0000000000000000 R14: ffff88804260f998 R15: 00007f90317cd000
 exit_mmap+0x2b2/0x510 mm/mmap.c:3091
 __mmput kernel/fork.c:1015 [inline]
 mmput+0x14e/0x4a0 kernel/fork.c:1036
 exit_mm kernel/exit.c:546 [inline]
 do_exit+0xac8/0x2f30 kernel/exit.c:867
 do_group_exit+0x125/0x350 kernel/exit.c:983
 get_signal+0x3ec/0x1f90 kernel/signal.c:2588
 do_signal+0x8f/0x1710 arch/x86/kernel/signal.c:821
 exit_to_usermode_loop+0x22b/0x2b0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c849
Code: Bad RIP value.
RSP: 002b:00007f902f9cbcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000076bf08 RCX: 000000000045c849
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000076bf08
RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000076bf0c
R13: 00007ffd55312dcf R14: 00007f902f9cc9c0 R15: 000000000076bf0c