iptables : xtables lock ?

[buixor]

Report from a user : cs-firewall-bouncer fails to start with this error :

time="26-04-2022 21:37:20" level=info msg="ipset 'crowdsec-blacklists' doesn't exist, skip"
time="26-04-2022 21:37:20" level=info msg="Checking existing set"
time="26-04-2022 21:37:20" level=info msg="ipset set-up : /usr/sbin/ipset -exist create crowdsec-blacklists nethash timeout 300"
time="26-04-2022 21:37:21" level=info msg="Rule doesn't exist (/usr/sbin/iptables -C INPUT -m set --match-set crowdsec-blacklists src -j DROP)"
time="26-04-2022 21:37:21" level=info msg="iptables set-up : /usr/sbin/iptables -I INPUT -m set --match-set crowdsec-blacklists src -j DROP"
time="26-04-2022 21:37:21" level=warning msg="Error inserting set in iptables (/usr/sbin/iptables -I INPUT -m set --match-set crowdsec-blacklists src -j DROP): exit status 4 : Another app is currently holding the xtables lock. Perhaps you want to use the -w option?\n"
time="26-04-2022 21:37:21" level=fatal msg="iptables init failed: while inserting set in iptables: exit status 4"