WARNING in __rcu_read_unlock

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    2aa55dccf83d hns3: prevent building without CONFIG_INET
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15628f6d400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9655b05acfc97ff
dashboard link: https://syzkaller.appspot.com/bug?extid=43f6755d1c2e62743468
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=125fda8b400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=135e54cd400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+43f6755d1c2e62743468@xxxxxxxxxxxxxxxxxxxxxxxxx

IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
WARNING: CPU: 0 PID: -2035180937 at kernel/rcu/tree_plugin.h:438  
__rcu_read_unlock+0x266/0x2e0 kernel/rcu/tree_plugin.h:432
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: -2035180937 Comm:  Lïïïïï Not tainted 4.20.0-rc6+ #344
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+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x55c kernel/panic.c:188
 __warn.cold.8+0x20/0x45 kernel/panic.c:540
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:__rcu_read_unlock+0x266/0x2e0 kernel/rcu/tree_plugin.h:432
Code: 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 0f b6 04 02 84 c0 74 04 3c 03  
7e 6f 41 c7 84 24 70 03 00 00 00 00 00 00 e9 5a fe ff ff <0f> 0b e9 da fe  
ff ff 4c 89 f7 e8 1b 14 59 00 e9 2a fe ff ff 4c 89
RSP: 0018:ffff8881dae075e8 EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 1ffff1103b5c0ebe RCX: ffffffff8153f599
RDX: 1ffff1103b5c0eca RSI: ffffffff8153f5bb RDI: 0000000000000005
RBP: ffff8881dae076b8 R08: ffff8881bf1f4540 R09: ffffed103b5c3ef8
R10: ffffed103b5c3ef8 R11: ffff8881dae1f7c7 R12: 00000000fdb21501
R13: 1ffff1103b5c0eca R14: ffff8881bf1f48b0 R15: ffff8881dae07690
 rcu_read_unlock include/linux/rcupdate.h:660 [inline]
 __atomic_notifier_call_chain kernel/notifier.c:184 [inline]
 atomic_notifier_call_chain+0xd0/0x190 kernel/notifier.c:193
 notify_die+0x1bd/0x2d0 kernel/notifier.c:549
 do_general_protection+0x16d/0x2f0 arch/x86/kernel/traps.c:557
 general_protection+0x1e/0x30 arch/x86/entry/entry_64.S:1142
RIP: 0010:task_css include/linux/cgroup.h:477 [inline]
RIP: 0010:task_ca kernel/sched/cpuacct.c:43 [inline]
RIP: 0010:cpuacct_account_field+0x140/0x3d0 kernel/sched/cpuacct.c:365
Code: b6 97 08 00 85 c0 74 0d 80 3d 69 bb b2 08 00 0f 84 a4 01 00 00 49 8d  
7e 10 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f  
85 4e 02 00 00 4d 8b 7e 10 49 81 ff 20 23 58 89 0f
RSP: 0018:ffff8881dae078a8 EFLAGS: 00010002
RAX: dffffc0000000000 RBX: ffff8881dae07918 RCX: 0000000000000000
RDX: 000000000000000e RSI: 00000000ffff8881 RDI: 0000000000000072
RBP: ffff8881dae07940 R08: 0000000000000000 R09: 0000000000000000
R10: ffffed1037304851 R11: 0000000000000007 R12: 0000000000982e14
R13: dffffc0000000000 R14: 0000000000000062 R15: ffff8881bf1f4540
 cgroup_account_cputime_field include/linux/cgroup.h:775 [inline]
 task_group_account_field kernel/sched/cputime.c:108 [inline]
 account_system_index_time+0x1e8/0x5d0 kernel/sched/cputime.c:171
 irqtime_account_process_tick.isra.6+0x35b/0x490 kernel/sched/cputime.c:388
 account_process_tick+0x282/0x350 kernel/sched/cputime.c:483
 update_process_times+0x21/0x70 kernel/time/timer.c:1634
 tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164
 tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274
 __run_hrtimer kernel/time/hrtimer.c:1398 [inline]
 __hrtimer_run_queues+0x41c/0x10d0 kernel/time/hrtimer.c:1460
 hrtimer_interrupt+0x313/0x780 kernel/time/hrtimer.c:1518
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1034 [inline]
 smp_apic_timer_interrupt+0x1a1/0x760 arch/x86/kernel/apic/apic.c:1059
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807
 </IRQ>
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches