[BUG] CAC countdown timer underflow

[Becker Béla]

Hello,

This is the second time this has occured to me in a few days. When selecting a DFS channel, the 60s timer can underflow, it winds up counting from UINT32_MAX.
I'm not able to reproduce this bug consistently, but I guess if I were to try again repeatedly it would randomly happen again.
Is this a known issue? I couldn't find any mention of this on the web.

The module I use is a SparkLAN WPEA-128N (AR9380), on an ARM cpu, running Linux 4.9.84.

root at passanger:~ # hostapd_cli status
Selected interface 'wlp4s0'
state=DFS
phy=phy1
freq=5580
num_sta_non_erp=0
num_sta_no_short_slot_time=0
num_sta_no_short_preamble=0
olbc=0
num_sta_ht_no_gf=0
num_sta_no_ht=0
num_sta_ht_20_mhz=0
num_sta_ht40_intolerant=0
olbc_ht=0
ht_op_mode=0x0
cac_time_seconds=60
cac_time_left_seconds=4294967006
channel=116
secondary_channel=0
ieee80211n=1
ieee80211ac=0
bss[0]=wlp4s0
bssid[0]=00:xx:xx:xx:xx:xx
ssid[0]=test_ap
num_sta[0]=0

root at passanger:~ # hostapd -v
hostapd v2.6
User space daemon for IEEE 802.11 AP management,
IEEE 802.1X/WPA/WPA2/EAP/RADIUS Authenticator
Copyright (c) 2002-2016, Jouni Malinen <j at w1.fi> and contributors

root at passanger:~ # uname -a
Linux passanger 4.9.84-2.8.2+gb2a7f2f #13 SMP Thu Apr 26 18:15:49 UTC 2018 armv7l armv7l armv7l GNU/Linux