------------[ cut here ]------------
WARNING: CPU: 3 PID: 1384 at /home/seg/DEV/mt7621/src/router/private/compat-wireless-2017-09-03/net/mac80211/sta_info.c:1909 _598+0x110/0x214 [mac80211]
STA f6:2e:47:d4:1f:71 AC 0 txq pending airtime underflow: 4294966992, 304
Modules linked in: nf_nat_pptp nf_conntrack_pptp nf_nat_proto_gre nf_conntrack_proto_gre fast_classifier mt7615e mt76 mac80211 compat [last unloaded: nf_conntrack_proto_gre]
CPU: 3 PID: 1384 Comm: hostapd Not tainted 4.14.170 #184
Stack : 00000000 00000200 87df1670 8007e0a4 80490000 8048ac0c 80610000 805ace24
        80586c9c 87c0fc74 870d845c 805ee787 805809e4 00000001 87c0fc18 805f4018
        00000000 00000000 80650000 00000000 81147bb8 0000010d 00000007 00000000
        00000000 80660000 80660000 68203a6d 80000000 80610000 00000000 872078ac
        87297244 00000775 00000000 00000200 00000000 8022f688 0000000c 8065000c
        ...
Call Trace:
[<800153a0>] show_stack+0x58/0x100
[<804376b4>] dump_stack+0xa4/0xe0
[<80034f90>] __warn+0xe4/0x144
[<80034bcc>] warn_slowpath_fmt+0x30/0x3c
[<872078ac>] _598+0x110/0x214 [mac80211]
[<87203180>] _634+0xb00/0xdc4 [mac80211]
---[ end trace f2e3bcabb460f384 ]---