1 lock held by udevd/10384:
 #0: ffff888100abc148 (&root->kernfs_rwsem){++++}-{3:3}, at: kernfs_dop_revalidate+0xf0/0x5a0 fs/kernfs/dir.c:1159
1 lock held by udevd/10419:
 #0: ffffffff88ec6a38 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock+0x282/0x3b0 kernel/rcu/tree_exp.h:297
=============================================
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	(detected by 1, t=11268 jiffies, g=41049, q=59 ncpus=2)
rcu: All QSes seen, last rcu_preempt kthread activity 11264 (4294971270-4294960006), jiffies_till_next_fqs=1, root ->qsmask 0x0
rcu: rcu_preempt kthread starved for 11264 jiffies! g41049 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:27760 pid:16    tgid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x105f/0x34b0 kernel/sched/core.c:6690
 __schedule_loop kernel/sched/core.c:6767 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6782
 schedule_timeout+0x136/0x2a0 kernel/time/timer.c:2615
 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2045
 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2247
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>