rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14375/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=106745, q=489 ncpus=2)
task:udevd           state:R  running task     stack:24256 pid:14375 tgid:14375 ppid:4675   flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x21/0x550 kernel/locking/lockdep.c:5727
Code: 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 81 ec 20 01 00 00 4c 89 4c 24 28 <4c> 89 44 24 38 48 89 4c 24 30 89 54 24 1c 41 89 f6 48 89 7c 24 20
RSP: 0018:ffffc9000323f280 EFLAGS: 00000282
RAX: ffffffff81e84132 RBX: dffffc0000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8e9382a0
RBP: ffffc9000323f3c8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff52000647f0a R12: 1ffff92000647e80
R13: ffff88806ba290f0 R14: dffffc0000000000 R15: ffffc9000323f520
 rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 __pte_offset_map+0x9e/0x380 mm/pgtable-generic.c:287
 __pte_offset_map_lock+0xc7/0x300 mm/pgtable-generic.c:371
 pte_offset_map_lock include/linux/mm.h:2985 [inline]
 zap_pte_range mm/memory.c:1597 [inline]
 zap_pmd_range mm/memory.c:1736 [inline]
 zap_pud_range mm/memory.c:1765 [inline]
 zap_p4d_range mm/memory.c:1786 [inline]
 unmap_page_range+0x95e/0x42c0 mm/memory.c:1807
 unmap_vmas+0x3cc/0x5f0 mm/memory.c:1897
 exit_mmap+0x264/0xc80 mm/mmap.c:3412
 __mmput+0x115/0x390 kernel/fork.c:1345
 exit_mm+0x220/0x310 kernel/exit.c:571
 do_exit+0x9b2/0x27f0 kernel/exit.c:869
 do_group_exit+0x207/0x2c0 kernel/exit.c:1031
 __do_sys_exit_group kernel/exit.c:1042 [inline]
 __se_sys_exit_group kernel/exit.c:1040 [inline]
 __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040
 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f39838fca90
RSP: 002b:00007ffe6bd07e98 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f39838fca90
RDX: 00000000000000e7 RSI: 000000000000003c RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000007 R09: 0bd7673906ae7bd0
R10: 00000000ffffffff R11: 0000000000000202 R12: 000055b7fc89d7d0
R13: 00007ffe6bd07ed8 R14: 0000000000000001 R15: 000055b7fc868910
 </TASK>
rcu: rcu_preempt kthread starved for 9990 jiffies! g106745 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:24464 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x1800/0x4a60 kernel/sched/core.c:6529
 __schedule_loop kernel/sched/core.c:6606 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6621
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236
 kthread+0x2f2/0x390 kernel/kthread.c:389
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline]
NMI backtrace for cpu 1 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111