rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4530/1:b..l
	(detected by 0, t=10502 jiffies, g=17985, q=168 ncpus=2)
task:udevd           state:R  running task     stack:23680 pid:4530  ppid:3636   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710
Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f
RSP: 0018:ffffc900050af6d8 EFLAGS: 00000206
RAX: 994e4bf55ea19f00 RBX: ffff88802524bb80 RCX: 994e4bf55ea19f00
RDX: 0000000000000000 RSI: ffffffff8a6c1780 RDI: ffffffff8abef920
RBP: 0000000000000001 R08: ffff88802524bb80 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000246 R14: ffff8880798a0158 R15: ffff88802524c660
 lock_is_held include/linux/lockdep.h:283 [inline]
 mt_locked lib/maple_tree.c:-1 [inline]
 mt_slot lib/maple_tree.c:816 [inline]
 mas_slot lib/maple_tree.c:849 [inline]
 mt_validate_nulls lib/maple_tree.c:7193 [inline]
 mt_validate+0x43ce/0x4c90 lib/maple_tree.c:7249
 validate_mm_mt+0xcd/0x420 mm/mmap.c:295
 validate_mm+0xcc/0x2b0 mm/mmap.c:332
 remove_mt mm/mmap.c:2322 [inline]
 do_mas_align_munmap+0xf98/0x1220 mm/mmap.c:2595
 do_mas_munmap+0x240/0x2b0 mm/mmap.c:2650
 __vm_munmap+0x18d/0x290 mm/mmap.c:2936
 __do_sys_munmap mm/mmap.c:2961 [inline]
 __se_sys_munmap mm/mmap.c:2958 [inline]
 __x64_sys_munmap+0x5c/0x70 mm/mmap.c:2958
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fabccf1e097
RSP: 002b:00007fffac6f4b78 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
RAX: ffffffffffffffda RBX: 000055698e57fce0 RCX: 00007fabccf1e097
RDX: 000055698e58fa88 RSI: 0000000000000200 RDI: 00007fabcd5c4000
RBP: 000055698e58fcc0 R08: 0000000000000030 R09: 0000000000040000
R10: 000055698e58fcb0 R11: 0000000000000246 R12: 00007fabcd7117c0
R13: 00007fabcd71339c R14: 0000000000000022 R15: 0000000000000001
 </TASK>
rcu: rcu_preempt kthread starved for 10519 jiffies! g17985 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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2168
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </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:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741