rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	1-...!: (1 ticks this GP) idle=bca/1/0x4000000000000000 softirq=132055/132055 fqs=0 
	(detected by 0, t=10502 jiffies, g=210737, q=7393)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2407 Comm: systemd-udevd Not tainted 5.9.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:match_held_lock+0xa/0x170 kernel/locking/lockdep.c:4488
Code: c4 48 c7 c6 c0 a6 4b 88 48 c7 c7 00 a7 4b 88 e8 ce c2 51 f9 0f 0b 5b c3 c3 0f 1f 80 00 00 00 00 48 39 77 10 0f 84 99 00 00 00 <66> f7 47 22 f0 ff 74 4f 55 53 48 83 ec 10 48 8b 46 08 48 85 c0 0f
RSP: 0018:ffffc90000da8d58 EFLAGS: 00000083
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 1ffffffff1308721
RDX: dffffc0000000000 RSI: ffffffff89bd6840 RDI: ffff888047b20a68
RBP: ffff888047b20180 R08: 0000000000000000 R09: ffffffff8ab2368f
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89bd6840
R13: ffff888047b20a68 R14: ffff888047b20a68 R15: 0000000000000086
FS:  0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055cf4cb74160 CR3: 00000001dddec000 CR4: 00000000001526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __lock_is_held kernel/locking/lockdep.c:4779 [inline]
 lock_is_held_type+0x72/0xf0 kernel/locking/lockdep.c:5042
 lock_is_held include/linux/lockdep.h:267 [inline]
 rcu_read_lock_sched_held+0x3a/0xb0 kernel/rcu/update.c:136
 trace_hrtimer_start include/trace/events/timer.h:195 [inline]
 debug_activate kernel/time/hrtimer.c:481 [inline]
 enqueue_hrtimer+0x346/0x3f0 kernel/time/hrtimer.c:969
 __run_hrtimer kernel/time/hrtimer.c:1541 [inline]
 __hrtimer_run_queues+0xc1e/0xfc0 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0x32a/0x930 kernel/time/hrtimer.c:1650
 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
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </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+0xb2/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:770 [inline]
RIP: 0010:lock_acquire+0x27b/0xad0 kernel/locking/lockdep.c:5008
Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 f8 06 00 00 48 83 3d aa ce 5b 08 00 0f 84 a6 05 00 00 48 8b 7c 24 08 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 03 44 24 10 48 c7
RSP: 0018:ffffc9001a377858 EFLAGS: 00000286
RAX: 1ffffffff136c779 RBX: ffff888047b20180 RCX: 00000000207dde82
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: 0000000000000286
RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c5f39e7
R10: fffffbfff18be73c R11: 0000000000000000 R12: 0000000000000002
R13: ffffffff89bd6900 R14: 0000000000000000 R15: ffff8880907bd7a8
 rcu_lock_acquire include/linux/rcupdate.h:241 [inline]
 rcu_read_lock include/linux/rcupdate.h:634 [inline]
 lock_page_memcg+0x63/0x260 mm/memcontrol.c:2094
 page_remove_rmap+0x25/0x1690 mm/rmap.c:1328
 zap_pte_range mm/memory.c:1091 [inline]
 zap_pmd_range mm/memory.c:1195 [inline]
 zap_pud_range mm/memory.c:1224 [inline]
 zap_p4d_range mm/memory.c:1245 [inline]
 unmap_page_range+0xf3c/0x2b20 mm/memory.c:1266
 unmap_single_vma+0x198/0x300 mm/memory.c:1311
 unmap_vmas+0x168/0x2e0 mm/memory.c:1343
 exit_mmap+0x2b1/0x530 mm/mmap.c:3183
 __mmput+0x122/0x470 kernel/fork.c:1076
 mmput+0x53/0x60 kernel/fork.c:1097
 exit_mm kernel/exit.c:483 [inline]
 do_exit+0xa8b/0x29f0 kernel/exit.c:793
 do_group_exit+0x125/0x310 kernel/exit.c:903
 __do_sys_exit_group kernel/exit.c:914 [inline]
 __se_sys_exit_group kernel/exit.c:912 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:912
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7fcafd5eb618
Code: Bad RIP value.
RSP: 002b:00007fff56381528 EFLAGS: 00000206 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 00007fff563815f0 RCX: 00007fcafd5eb618
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00007fff563816a0 R08: 00000000000000e7 R09: fffffffffffffe50
R10: 00000000ffffffff R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000003 R15: 000000000000000e
rcu: rcu_preempt kthread starved for 10502 jiffies! g210737 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:
task:rcu_preempt     state:I stack:28288 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0x8e5/0x21e0 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x148/0x250 kernel/time/timer.c:1879
 rcu_gp_fqs_loop kernel/rcu/tree.c:1888 [inline]
 rcu_gp_kthread+0xae5/0x1b50 kernel/rcu/tree.c:2058
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294