INFO: rcu detected stall in neigh_timer_handler

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 4c5bf01e Linux 4.14.161
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=108b9ab9e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=b10bf1ad4786130a
dashboard link: https://syzkaller.appspot.com/bug?extid=6e52d84ca9c021bc0e16
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6e52d8...@syzkaller.appspotmail.com

protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
INFO: rcu_preempt self-detected stall on CPU
1-...: (6615 ticks this GP) idle=1ae/140000000000002/0
softirq=262951/262951 fqs=4
(t=10500 jiffies g=70377 c=70376 q=8)
rcu_preempt kthread starved for 10107 jiffies! g70377 c70376 f0x0
RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0
rcu_preempt R running task 29776 8 2 0x80000000
Call Trace:
context_switch kernel/sched/core.c:2808 [inline]
__schedule+0x7b8/0x1cd0 kernel/sched/core.c:3384
schedule+0x92/0x1c0 kernel/sched/core.c:3428
schedule_timeout+0x43e/0xe10 kernel/time/timer.c:1746
rcu_gp_kthread+0xbf4/0x1ec0 kernel/rcu/tree.c:2255
kthread+0x319/0x430 kernel/kthread.c:232
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
NMI backtrace for cpu 1
CPU: 1 PID: 23469 Comm: syz-executor.4 Not tainted 4.14.161-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+0x142/0x197 lib/dump_stack.c:58
nmi_cpu_backtrace.cold+0x57/0x94 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x141/0x189 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:158 [inline]
rcu_dump_cpu_stacks+0x186/0x1d2 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+0x43d/0xd0a kernel/rcu/tree.c:2792
update_process_times+0x31/0x70 kernel/time/timer.c:1590
tick_sched_handle+0x85/0x160 kernel/time/tick-sched.c:161
tick_sched_timer+0x43/0x130 kernel/time/tick-sched.c:1219
__run_hrtimer kernel/time/hrtimer.c:1220 [inline]
__hrtimer_run_queues+0x270/0xbc0 kernel/time/hrtimer.c:1284
hrtimer_interrupt+0x1d8/0x5d0 kernel/time/hrtimer.c:1318
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1075 [inline]
smp_apic_timer_interrupt+0x11c/0x5e0 arch/x86/kernel/apic/apic.c:1100
apic_timer_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:792
RIP: 0010:update_stack_state+0x3c5/0x590 arch/x86/kernel/unwind_frame.c:218
RSP: 0018:ffff8880aed07798 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff10
RAX: ffff8880aed07bd8 RBX: ffff8880aed07908 RCX: 1ffff11015da0f28
RDX: 1ffff11015da0f79 RSI: ffff8880aed07c08 RDI: ffff8880aed07940
RBP: ffff8880aed07840 R08: 0000000000000001 R09: ffff8880aed07960
R10: ffff8880aed07930 R11: ffff8880aed07940 R12: 1ffff11015da0f0f
R13: ffff8880aed07908 R14: 1ffff11015da0efb R15: ffff8880aed07c08
unwind_next_frame.part.0+0x188/0x8b0 arch/x86/kernel/unwind_frame.c:333
unwind_next_frame+0x3b/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6b/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x45/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc mm/kasan/kasan.c:551 [inline]
kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:489
slab_post_alloc_hook mm/slab.h:442 [inline]
slab_alloc mm/slab.c:3390 [inline]
kmem_cache_alloc+0x11b/0x780 mm/slab.c:3550
skb_clone+0x129/0x320 net/core/skbuff.c:1282
neigh_probe+0x59/0x100 net/core/neighbour.c:910
neigh_timer_handler+0x264/0xa70 net/core/neighbour.c:994
call_timer_fn+0x161/0x670 kernel/time/timer.c:1279
expire_timers kernel/time/timer.c:1318 [inline]
__run_timers kernel/time/timer.c:1636 [inline]
__run_timers kernel/time/timer.c:1604 [inline]
run_timer_softirq+0x5b7/0x1520 kernel/time/timer.c:1649
__do_softirq+0x244/0x9a0 kernel/softirq.c:288
invoke_softirq kernel/softirq.c:368 [inline]
irq_exit+0x160/0x1b0 kernel/softirq.c:409
exiting_irq arch/x86/include/asm/apic.h:648 [inline]
smp_apic_timer_interrupt+0x146/0x5e0 arch/x86/kernel/apic/apic.c:1102
apic_timer_interrupt+0x96/0xa0 arch/x86/entry/entry_64.S:792
</IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:779
[inline]
RIP: 0010:__down_trylock_console_sem+0xee/0x200 kernel/printk/printk.c:229
RSP: 0018:ffff88805ec975f0 EFLAGS: 00000297 ORIG_RAX: ffffffffffffff10
RAX: ffff888096f72180 RBX: 0000000000000297 RCX: 1ffff11012dee544
RDX: 0000000000000000 RSI: ffff888096f72a00 RDI: 0000000000000297
RBP: ffff88805ec97608 R08: ffff888096f72180 R09: ffff888096f72a20
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffffffff814b616b R14: ffff88805ec976f0 R15: 0000000000000000
console_trylock+0x17/0x80 kernel/printk/printk.c:2234
console_trylock_spinning kernel/printk/printk.c:1650 [inline]
vprintk_emit kernel/printk/printk.c:1922 [inline]
vprintk_emit+0x1eb/0x600 kernel/printk/printk.c:1888
vprintk_default+0x28/0x30 kernel/printk/printk.c:1963
vprintk_func+0x5d/0x159 kernel/printk/printk_safe.c:401
printk+0x9e/0xbc kernel/printk/printk.c:1996
kset_release+0x4a/0x57 lib/kobject.c:870
kobject_cleanup lib/kobject.c:646 [inline]
kobject_release lib/kobject.c:675 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put.cold+0x269/0x2f9 lib/kobject.c:692
kset_unregister+0x38/0x50 lib/kobject.c:835
remove_queue_kobjects net/core/net-sysfs.c:1425 [inline]
netdev_unregister_kobject+0x172/0x1d0 net/core/net-sysfs.c:1561
rollback_registered_many+0x694/0xb60 net/core/dev.c:7238
rollback_registered+0xdd/0x180 net/core/dev.c:7256
unregister_netdevice_queue net/core/dev.c:8249 [inline]
unregister_netdevice_queue+0x1ae/0x230 net/core/dev.c:8242
unregister_netdevice include/linux/netdevice.h:2442 [inline]
__tun_detach+0xa8c/0xce0 drivers/net/tun.c:576
tun_detach drivers/net/tun.c:586 [inline]
tun_chr_close+0x46/0x60 drivers/net/tun.c:2660
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0x7be/0x2c80 kernel/exit.c:854
do_group_exit+0x111/0x330 kernel/exit.c:951
get_signal+0x381/0x1cd0 kernel/signal.c:2413
do_signal+0x86/0x19a0 arch/x86/kernel/signal.c:814
exit_to_usermode_loop+0x15c/0x220 arch/x86/entry/common.c:160
prepare_exit_to_usermode+0x1b5/0x220 arch/x86/entry/common.c:199
retint_user+0x8/0x18
RIP: 0033:0x403dc0
RSP: 002b:00007f7278608c88 EFLAGS: 00000202 ORIG_RAX: ffffffffffffff10
RAX: 00007f727a60a000 RBX: 0000000000000005 RCX: 0000000000000005
RDX: 000000000015dae8 RSI: 0000000000000000 RDI: 000000000075bfa8
RBP: 000000000075bf20 R08: 0000000000000009 R09: 0000000000000000
R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000075bf70
R13: 00000000004c1707 R14: 00000000004d6200 R15: 00000000ffffffff
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
net_ratelimit: 3 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
net_ratelimit: 8 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
net_ratelimit: 13 callbacks suppressed
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1


---
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[syzbot]

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