rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P16361/1:b..l P9883/1:b..l
	(detected by 1, t=10502 jiffies, g=114997, q=409 ncpus=2)
task:udevd           state:R  running task     stack:23296 pid:9883  ppid:3637   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:391 [inline]
 lockref_put_or_lock+0x6e/0xb0 lib/lockref.c:151
 fast_dput+0x154/0x280 fs/dcache.c:779
 dput+0xd9/0x1d0 fs/dcache.c:905
 path_put fs/namei.c:561 [inline]
 do_unlinkat+0x4c6/0x560 fs/namei.c:4406
 __do_sys_unlink fs/namei.c:4438 [inline]
 __se_sys_unlink fs/namei.c:4436 [inline]
 __x64_sys_unlink+0x45/0x50 fs/namei.c:4436
 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: 0033:0x7fd9a0a4f937
RSP: 002b:00007ffcced51e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 00007ffcced51e80 RCX: 00007fd9a0a4f937
RDX: 0000000000000000 RSI: 00000000000007cd RDI: 00007ffcced52a80
RBP: 0000563003c911c0 R08: 0000563003c9c5c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000563003c89830
R13: 00007ffcced52a80 R14: 0000000000000000 R15: 00007ffcced52280
 </TASK>
task:sed             state:R  running task     stack:24064 pid:16361 ppid:16358  flags:0x00004000
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:mas_validate_parent_slot lib/maple_tree.c:7050 [inline]
RIP: 0010:mt_validate+0x120d/0x4c90 lib/maple_tree.c:7240
Code: 4a 8c ba 94 1b 00 00 e9 e3 fe ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 0f fd ff ff 4c 89 e7 e8 e8 c1 cb f7 e9 02 fd ff ff <e8> ce 94 7b f7 48 8b 9c 24 38 01 00 00 41 89 df 41 c1 ef 03 41 83
RSP: 0018:ffffc90004457880 EFLAGS: 00000246
RAX: ffffffff8a053845 RBX: 0000000000000009 RCX: ffff88802f42d940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000009
RBP: ffffc90004457a50 R08: 0000000000000004 R09: 0000000000000003
R10: fffffbfff2e0b094 R11: 1ffffffff2e0b094 R12: dffffc0000000000
R13: 0000000000000000 R14: 0000000000000000 R15: ffff8880618c3698
 validate_mm_mt+0xcd/0x420 mm/mmap.c:295
 validate_mm+0xcc/0x2b0 mm/mmap.c:332
 do_mmap+0xc7/0xfd0 mm/mmap.c:1270
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1482
 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: 0033:0x7f1acff7c242
RSP: 002b:00007fffee34cba8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f1acfc56000 RCX: 00007f1acff7c242
RDX: 0000000000000001 RSI: 0000000000002000 RDI: 00007f1acfc56000
RBP: 0000000000000812 R08: 0000000000000003 R09: 0000000000005000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007fffee34cc30
R13: 00007f1acfc5b0c0 R14: 00007fffee34cfe0 R15: 00000ffffdc69978
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 1896 jiffies! g114997 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=0 timer-softirq=100550
rcu: rcu_preempt kthread starved for 1902 jiffies! g114997 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
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:27200 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:1965
 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 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741