Wifi drops from time to time

hello,

from time to time the wifi breaks (lan works fine) with the following log:

Sat Apr  9 15:28:41 2022 daemon.notice hostapd: wlan1: AP-STA-DISCONNECTED 60:6d:c7:eb:f3:81
Sat Apr  9 15:28:41 2022 daemon.info hostapd: wlan1: STA 60:6d:c7:eb:f3:81 IEEE 802.11: authenticated
Sat Apr  9 15:28:41 2022 daemon.info hostapd: wlan1: STA 60:6d:c7:eb:f3:81 IEEE 802.11: associated (aid 2)
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.413256] ------------[ cut here ]------------
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.418305] WARNING: CPU: 0 PID: 1494 at backports-5.10.68-1/net/mac80211/rate.c:677 0x8769e700 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.429992] Modules linked in: ath9k ath9k_common pppoe ppp_async iptable_nat ath9k_hw ath10k_pci ath10k_core ath xt_state xt_nat xt_conntrack xt_REDIRECT xt_MASQUERADE xt_FLOWOFFLOAD xt_CT pptp pppox ppp_mppe ppp_generic nf_nat_tftp nf_nat_snmp_basic nf_nat_sip nf_nat_pptp nf_nat_irc nf_nat_h323 nf_nat_amanda nf_nat nf_flow_table_hw nf_flow_table nf_conntrack_tftp nf_conntrack_snmp nf_conntrack_sip nf_conntrack_pptp nf_conntrack_irc nf_conntrack_h323 nf_conntrack_broadcast nf_conntrack_amanda nf_conntrack mac80211 ipt_REJECT cfg80211 xt_time xt_tcpudp xt_multiport xt_mark xt_mac xt_limit xt_comment xt_TCPMSS xt_LOG ts_kmp ts_fsm ts_bm slhc nf_reject_ipv4 nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 iptable_raw iptable_mangle iptable_filter ip_tables hwmon crc_ccitt compat asn1_decoder nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables ip6t_REJECT x_tables nf_reject_ipv6 ip_gre gre ip_tunnel sha1_generic ecb arc4 aead cryptomgr crypto_null crypto_hash gpio_button_hotplug
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.520415] CPU: 0 PID: 1494 Comm: hostapd Tainted: G        W         5.4.154 #0
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.528323] Stack : 87700000 800b98ec 80660000 805fa498 00000000 00000000 00000000 00000000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.537142]         00000000 00000000 00000000 00000000 00000000 00000001 86b2b968 a5d6376a
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.545962]         86b2ba00 00000000 00000000 0000143e 00000038 8057ac04 352e342e 31353420
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.554775]         0000143e 1f83402f 00000000 0007f0df 80000000 86b2b948 00000000 8769e700
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.563591]         00000009 876f6760 869201a0 80630000 00000002 8032041c 00000000 80790000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.572418]         ...
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.575124] Call Trace:
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.575156] [<800b98ec>] 0x800b98ec
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.581649] [<80660000>] 0x80660000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.585443] [<8057ac04>] 0x8057ac04
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.589249] [<8769e700>] 0x8769e700 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.595558] [<8032041c>] 0x8032041c
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.599361] [<80069364>] 0x80069364
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.603149] [<8006936c>] 0x8006936c
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.606935] [<800824f4>] 0x800824f4
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.610736] [<8769e700>] 0x8769e700 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.617036] [<8008259c>] 0x8008259c
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.620828] [<8688af48>] 0x8688af48 [ath9k@0d32e7e6+0x19450]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.626870] [<8769e700>] 0x8769e700 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.633174] [<804505a8>] 0x804505a8
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.636976] [<804505a8>] 0x804505a8
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.640777] [<876b2154>] 0x876b2154 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.647101] [<8688b908>] 0x8688b908 [ath9k@0d32e7e6+0x19450]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.653167] [<8688ba64>] 0x8688ba64 [ath9k@0d32e7e6+0x19450]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.659211] [<876b2c3c>] 0x876b2c3c [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.665525] [<876b8768>] 0x876b8768 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.671854] [<876b8bc4>] 0x876b8bc4 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.678182] [<876ba838>] 0x876ba838 [mac80211@e397f870+0x7cdb0]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.684479] [<803e1450>] 0x803e1450
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.688274] [<86884eb8>] 0x86884eb8 [ath9k@0d32e7e6+0x19450]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.694307] [<80660000>] 0x80660000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.698095] [<80660000>] 0x80660000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.701884] [<80085380>] 0x80085380
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.705675] [<80580170>] 0x80580170
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.709463] [<80660000>] 0x80660000
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.713257] [<80085558>] 0x80085558
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.717060] [<8008563c>] 0x8008563c
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.720846] [<803ddefc>] 0x803ddefc
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.724641] [<80539324>] 0x80539324
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.728439] [<8053e1fc>] 0x8053e1fc
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.732222] [<800a938c>] 0x800a938c
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.736032] [<8057be18>] 0x8057be18
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.739836] [<8057c050>] 0x8057c050
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.743616] [<8057f8d8>] 0x8057f8d8
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.747418] [<803b91e8>] 0x803b91e8
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.751219] [<8057f970>] 0x8057f970
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.755031] [<800a1008>] 0x800a1008
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.758819] [<800b2278>] 0x800b2278
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.762614] [<80069e88>] 0x80069e88
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.766407] [<801e69d0>] 0x801e69d0
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.770196] [<8006dcac>] 0x8006dcac
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.773988]
Sat Apr  9 15:28:43 2022 kern.warn kernel: [5016444.775711] ---[ end trace 4b634d001922c2e1 ]---
Sat Apr  9 15:28:43 2022 daemon.notice hostapd: wlan1: AP-STA-CONNECTED 60:6d:c7:eb:f3:81
Sat Apr  9 15:28:43 2022 daemon.info hostapd: wlan1: STA 60:6d:c7:eb:f3:81 WPA: pairwise key handshake completed (RSN)
Sat Apr  9 15:28:43 2022 daemon.info dnsmasq-dhcp[2681]: DHCPREQUEST(br-lan) 192.168.1.231 60:6d:c7:eb:f3:81
Sat Apr  9 15:28:43 2022 daemon.info dnsmasq-dhcp[2681]: DHCPACK(br-lan) 192.168.1.231 60:6d:c7:eb:f3:81 DESKTOP-2N4VBIH

any hints?
TP-Link Archer C6 v2 (EU/RU/JP)
OpenWrt 21.02.1 r16325-88151b8303

Well, you might upgrade to 21.02.2 to see if some bug has already been fixed since the old release that you are currently using.

If problem is same as mentioned in the Tp-link Archer C60 v2...post ,
You can also consider using OpenWrt 19.07.9 ninth service release