rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P3547/2:b..l
	(detected by 1, t=10502 jiffies, g=33457, q=290)
task:udevd           state:R  running task     stack:19872 pid: 3547 ppid:     1 flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6780
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:rht_ptr_rcu include/linux/rhashtable.h:369 [inline]
RIP: 0010:__rhashtable_lookup include/linux/rhashtable.h:599 [inline]
RIP: 0010:rhashtable_lookup include/linux/rhashtable.h:638 [inline]
RIP: 0010:rhashtable_lookup_fast include/linux/rhashtable.h:664 [inline]
RIP: 0010:__netlink_lookup+0x270/0x710 net/netlink/af_netlink.c:499
Code: 74 24 30 0f 84 ea 01 00 00 e8 7c 67 70 f9 4c 8b 74 24 38 48 8b 44 24 40 42 80 3c 20 00 74 08 4c 89 f7 e8 b3 da b5 f9 4d 8b 36 <e8> 0b dc 99 01 41 89 c7 31 ff 89 c6 e8 af 6a 70 f9 45 85 ff 74 21
RSP: 0018:ffffc90002eaf830 EFLAGS: 00000246
RAX: 1ffff1100bfc619f RBX: 00000000b135e76f RCX: ffff88805fe30c00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 1ffff110288f2b1d R08: 00000000ffffffff R09: fffffbfff1ff3219
R10: fffffbfff1ff3219 R11: 1ffffffff1ff3218 R12: dffffc0000000000
R13: ffff88805fe30c04 R14: ffff888076a916d8 R15: 000000000000000f
 netlink_lookup+0xb3/0x1d0 net/netlink/af_netlink.c:519
 netlink_getsockbyportid net/netlink/af_netlink.c:1145 [inline]
 netlink_unicast+0x125/0x920 net/netlink/af_netlink.c:1331
 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fbd01e27a4b
RSP: 002b:00007ffd14bb4348 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00005603578d29e0 RCX: 00007fbd01e27a4b
RDX: 0000000000000000 RSI: 00007ffd14bb4358 RDI: 0000000000000004
RBP: 00005603578f7ec0 R08: 0000000000000001 R09: 0000000000000000
R10: 000000000000010f R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000000b4 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 9929 jiffies! g33457 f0x0 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:R  running task     stack:27584 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914
 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </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:722