rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4674/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=50613, q=406 ncpus=2)
task:udevd           state:R  running task     stack:22240 pid:4674  tgid:4674  ppid:1      flags:0x00000002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x17ae/0x4a10 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+0x104/0x550 kernel/locking/lockdep.c:5732
Code: 87 0e 73 16 e8 cd f5 09 00 84 c0 75 0d 80 3d ea 50 71 0e 00 0f 84 f9 02 00 00 48 c7 c0 3c 7d f7 8f 48 c1 e8 03 42 0f b6 04 28 <84> c0 0f 85 ff 02 00 00 83 3d 49 b0 87 0e 00 0f 84 42 01 00 00 65
RSP: 0018:ffffc900031bf980 EFLAGS: 00000a03
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff816fccb4
RDX: 0000000000000000 RSI: ffffffff8c3fba60 RDI: ffffffff8c3fba20
RBP: ffffc900031bfad8 R08: ffffffff8ff74aef R09: 1ffffffff1fee95d
R10: dffffc0000000000 R11: fffffbfff1fee95e R12: 1ffff92000637f38
R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff1100ac29664
 rcu_lock_acquire include/linux/rcupdate.h:326 [inline]
 rcu_read_lock include/linux/rcupdate.h:838 [inline]
 path_init+0x146/0x1360 fs/namei.c:2437
 path_lookupat+0x27/0x450 fs/namei.c:2556
 filename_lookup+0x256/0x610 fs/namei.c:2595
 do_readlinkat+0xf0/0x3a0 fs/stat.c:537
 __do_sys_readlink fs/stat.c:574 [inline]
 __se_sys_readlink fs/stat.c:571 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:571
 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: 0033:0x7f1d19d17d47
RSP: 002b:00007fff90da08f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007fff90da0908 RCX: 00007f1d19d17d47
RDX: 0000000000000400 RSI: 00007fff90da0908 RDI: 00007fff90da0de8
RBP: 0000000000000400 R08: 000055cd39ba89a4 R09: 0000000000000000
R10: 0000000000000812 R11: 0000000000000246 R12: 00007fff90da0de8
R13: 00007fff90da0d58 R14: 000055cd39b94910 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10532 jiffies! g50613 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:25816 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5188 [inline]
 __schedule+0x17ae/0x4a10 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+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/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