INFO: rcu detected stall in bind

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbfa1702 Linux 4.14.198
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17d05a75900000
kernel config: https://syzkaller.appspot.com/x/.config?x=3990958d85b55e59
dashboard link: https://syzkaller.appspot.com/bug?extid=c478ade1c9e5e39d8496
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c478ad...@syzkaller.appspotmail.com

INFO: rcu_preempt detected stalls on CPUs/tasks:
(detected by 1, t=10502 jiffies, g=111041, c=111040, q=1280)
All QSes seen, last rcu_preempt kthread activity 10502 (4295188297-4295177795), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.3 R running task 28912 19112 20942 0x0000000a
Call Trace:
<IRQ>
sched_show_task.cold+0x333/0x39a kernel/sched/core.c:5169
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+0xd29/0xd99 kernel/rcu/tree.c:2792
update_process_times+0x28/0xa0 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:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
RSP: 0018:ffff88820e71fb40 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10
RAX: 1ffffffff0fa2d24 RBX: ffffffff887beb2c RCX: 1ffff11004413d37
RDX: dffffc0000000000 RSI: ffff88802209e998 RDI: ffff88802209e944
RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000286
R13: dffffc0000000000 R14: ffffffff887beb2d R15: ffffed1015d65828
arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
kvm_wait arch/x86/kernel/kvm.c:600 [inline]
kvm_wait+0x179/0x240 arch/x86/kernel/kvm.c:580
pv_wait arch/x86/include/asm/paravirt.h:679 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:447 [inline]
__pv_queued_spin_lock_slowpath+0x722/0x910 kernel/locking/qspinlock.c:465
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:669 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:52 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:90 [inline]
queued_read_lock_slowpath+0x150/0x190 kernel/locking/qrwlock.c:90
hci_send_to_channel+0x2c/0x1a0 net/bluetooth/hci_sock.c:261
hci_send_monitor_ctrl_event+0x3dd/0x500 net/bluetooth/hci_sock.c:391
mgmt_send_event+0x2b3/0x330 net/bluetooth/mgmt_util.c:86
mgmt_index_event net/bluetooth/mgmt.c:253 [inline]
mgmt_index_added+0x1d5/0x210 net/bluetooth/mgmt.c:6554
hci_sock_bind+0xddf/0xfe0 net/bluetooth/hci_sock.c:1184
SYSC_bind net/socket.c:1489 [inline]
SyS_bind+0x174/0x1f0 net/socket.c:1475
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45e179
RSP: 002b:00007efe49142c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000031
RAX: ffffffffffffffda RBX: 0000000000000b40 RCX: 000000000045e179
RDX: 0000000000000006 RSI: 0000000020000100 RDI: 0000000000000004
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007fffbae94e6f R14: 00007efe491439c0 R15: 000000000118cf4c
rcu_preempt kthread starved for 10502 jiffies! g111041 c111040 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_preempt R running task 30008 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:1754
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


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.