INFO: rcu_sched self-detected stall on CPU
	1-...: (10499 ticks this GP) idle=aa6/140000000000001/0 softirq=144602/144603 fqs=0 
	 (t=10500 jiffies g=25875 c=25874 q=0)
rcu_sched kthread starved for 10500 jiffies! g25875 c25874 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_sched       R  running task    30008     9      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747
 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
NMI backtrace for cpu 1
CPU: 1 PID: 2011 Comm: syz-executor.4 Not tainted 4.14.216-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x180 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:158 [inline]
 rcu_dump_cpu_stacks+0x15f/0x19c kernel/rcu/tree.c:1396
 print_cpu_stall kernel/rcu/tree.c:1542 [inline]
 check_cpu_stall kernel/rcu/tree.c:1610 [inline]
 __rcu_pending kernel/rcu/tree.c:3390 [inline]
 rcu_pending kernel/rcu/tree.c:3452 [inline]
 rcu_check_callbacks.cold+0x464/0xd8d kernel/rcu/tree.c:2792
 update_process_times+0x29/0x60 kernel/time/timer.c:1591
 tick_sched_handle+0x7d/0x150 kernel/time/tick-sched.c:165
 tick_sched_timer+0x92/0x200 kernel/time/tick-sched.c:1223
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
 smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1100
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:27 [inline]
RIP: 0010:queued_write_lock_slowpath+0xcb/0x1d0 kernel/locking/qrwlock.c:139
RSP: 0018:ffff88804c95fd10 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000101 RBX: ffffffff89dd2ae8 RCX: 00000000000005fd
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff89dd2ae8
RBP: ffffffff89dd2aec R08: ffffffff8b98caa8 R09: 00000000000405a0
R10: ffff88804c8c0e98 R11: ffff88804c8c05c0 R12: 0000000000000003
R13: fffffbfff13ba55d R14: 00000000000000ff R15: ffff88809469dc90
 queued_write_lock include/asm-generic/qrwlock.h:134 [inline]
 do_raw_write_lock+0xc2/0x1d0 kernel/locking/spinlock_debug.c:203
 bt_sock_unlink+0x1d/0x170 net/bluetooth/af_bluetooth.c:151
 hci_sock_release+0xc1/0x4c0 net/bluetooth/hci_sock.c:850
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x417b71
RSP: 002b:00007ffd1d9e7cb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000417b71
RDX: fffffffffffffff7 RSI: 0000000000000081 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00000000011a0418 R09: 0000000000000000
R10: 00007ffd1d9e7d80 R11: 0000000000000293 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000003 R15: 000000000119bf8c
INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10536 jiffies, g=45482, c=45481, q=55)
All QSes seen, last rcu_preempt kthread activity 10536 (4295068299-4295057763), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.4  R  running task    28912  2011   8012 0x0000000a
Call Trace:
 <IRQ>
 sched_show_task.cold+0x333/0x39a kernel/sched/core.c:5165
 print_other_cpu_stall kernel/rcu/tree.c:1501 [inline]
 check_cpu_stall kernel/rcu/tree.c:1616 [inline]
 __rcu_pending kernel/rcu/tree.c:3390 [inline]
 rcu_pending kernel/rcu/tree.c:3452 [inline]
 rcu_check_callbacks.cold+0xd29/0xd8d kernel/rcu/tree.c:2792
 update_process_times+0x29/0x60 kernel/time/timer.c:1591
 tick_sched_handle+0x7d/0x150 kernel/time/tick-sched.c:165
 tick_sched_timer+0x92/0x200 kernel/time/tick-sched.c:1223
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
 smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1100
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:27 [inline]
RIP: 0010:queued_write_lock_slowpath+0xcb/0x1d0 kernel/locking/qrwlock.c:139
RSP: 0018:ffff88804c95fd10 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000101 RBX: ffffffff89dd2ae8 RCX: 00000000000005fd
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff89dd2ae8
RBP: ffffffff89dd2aec R08: ffffffff8b98caa8 R09: 00000000000405a0
R10: ffff88804c8c0e98 R11: ffff88804c8c05c0 R12: 0000000000000003
R13: fffffbfff13ba55d R14: 00000000000000ff R15: ffff88809469dc90
 queued_write_lock include/asm-generic/qrwlock.h:134 [inline]
 do_raw_write_lock+0xc2/0x1d0 kernel/locking/spinlock_debug.c:203
 bt_sock_unlink+0x1d/0x170 net/bluetooth/af_bluetooth.c:151
 hci_sock_release+0xc1/0x4c0 net/bluetooth/hci_sock.c:850
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x417b71
RSP: 002b:00007ffd1d9e7cb0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000417b71
RDX: fffffffffffffff7 RSI: 0000000000000081 RDI: 0000000000000004
RBP: 0000000000000000 R08: 00000000011a0418 R09: 0000000000000000
R10: 00007ffd1d9e7d80 R11: 0000000000000293 R12: ffffffffffffffff
R13: 0000000000000000 R14: 0000000000000003 R15: 000000000119bf8c
rcu_preempt kthread starved for 10536 jiffies! g45482 c45481 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_preempt     R  running task    29928     8      2 0x80000000
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x88b/0x1de0 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_timeout+0x4af/0xe90 kernel/time/timer.c:1747
 rcu_gp_kthread+0xc0a/0x1e60 kernel/rcu/tree.c:2255
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404