rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	1-...!: (10499 ticks this GP) idle=d8a/1/0x4000000000000002 softirq=115288/115288 fqs=0 
rcu: 	 (t=10500 jiffies g=165457 q=50)
rcu: rcu_preempt kthread starved for 10500 jiffies! g165457 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0
rcu: RCU grace-period kthread stack dump:
rcu_preempt     I25528    10      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2844 [inline]
 __schedule+0x897/0x1e60 kernel/sched/core.c:3485
 schedule+0xfe/0x350 kernel/sched/core.c:3529
 schedule_timeout+0x14a/0x250 kernel/time/timer.c:1803
 rcu_gp_fqs_loop+0x6ba/0x970 kernel/rcu/tree.c:1948
 rcu_gp_kthread+0x2bb/0xc10 kernel/rcu/tree.c:2105
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
NMI backtrace for cpu 1
CPU: 1 PID: 28752 Comm: syz-executor5 Not tainted 5.0.0-rc4+ #56
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1db/0x2d0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1be/0x236 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0x183/0x1cf kernel/rcu/tree.c:1211
 print_cpu_stall.cold+0x227/0x40c kernel/rcu/tree.c:1348
 check_cpu_stall kernel/rcu/tree.c:1422 [inline]
 rcu_pending kernel/rcu/tree.c:3018 [inline]
 rcu_check_callbacks+0xb32/0x1380 kernel/rcu/tree.c:2521
 update_process_times+0x32/0x80 kernel/time/timer.c:1635
 tick_sched_handle+0xa2/0x190 kernel/time/tick-sched.c:161
 tick_sched_timer+0x47/0x130 kernel/time/tick-sched.c:1271
 __run_hrtimer kernel/time/hrtimer.c:1389 [inline]
 __hrtimer_run_queues+0x3a7/0x1050 kernel/time/hrtimer.c:1451
 hrtimer_interrupt+0x314/0x770 kernel/time/hrtimer.c:1509
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1035 [inline]
 smp_apic_timer_interrupt+0x18d/0x760 arch/x86/kernel/apic/apic.c:1060
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:queued_write_lock_slowpath+0x220/0x460 kernel/locking/qrwlock.c:86
Code: 8b 03 84 c9 74 09 80 f9 03 0f 8e b8 01 00 00 48 89 de 41 89 44 24 b0 83 e6 07 41 c6 07 f8 83 c6 03 3d 00 01 00 00 74 42 f3 90 <48> 89 d8 41 c6 07 04 48 c1 e8 03 42 0f b6 04 30 40 38 c6 7c 08 84
RSP: 0018:ffff88806a4c78f0 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000300 RBX: ffffffff8a409ea0 RCX: 0000000000000004
RDX: 1ffff1100d498f27 RSI: 0000000000000003 RDI: ffffffff8a409ea0
RBP: ffff88806a4c79b0 R08: 1ffffffff14813d4 R09: fffffbfff14813d5
R10: fffffbfff14813d4 R11: ffffffff8a409ea3 R12: ffff88806a4c7988
R13: ffffffff8a409ea4 R14: dffffc0000000000 R15: ffffed100d498f27
 queued_write_lock include/asm-generic/qrwlock.h:104 [inline]
 do_raw_write_lock+0x27b/0x310 kernel/locking/spinlock_debug.c:203
 __raw_write_lock_bh include/linux/rwlock_api_smp.h:204 [inline]
 _raw_write_lock_bh+0x3b/0x50 kernel/locking/spinlock.c:312
 x25_remove_socket net/x25/af_x25.c:202 [inline]
 __x25_destroy_socket+0xa6/0x6b0 net/x25/af_x25.c:398
 x25_release+0x2d5/0x340 net/x25/af_x25.c:653
 __sock_release+0xd3/0x250 net/socket.c:579
 sock_close+0x1b/0x30 net/socket.c:1139
 __fput+0x3c5/0xb10 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x1f4/0x2b0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x32a/0x3b0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x696/0x800 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411d41
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 94 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffea5dd2c50 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000411d41
RDX: fffffffffffffff7 RSI: 0000000000740470 RDI: 0000000000000004
RBP: 0000000000000000 R08: 0000000000740468 R09: 00000000001213e5
R10: 00007ffea5dd2b70 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 000000000000088b R15: 0000000000000005