I noticed some weird kernel logs when my Linksys WRT1900ACS (LEDE 17.01.0) switches channel on the 5ghz wifi (from 100 to 36). Everything works fine, other than my wifi being on channel 36 now, because of dfs, I assume. But I thought maybe there is a bug in the mwlwifi (or is it just really verbose on a channel switch?) and someone can make something out of this.
On a client (named "zora"):
Feb 26 14:19:01 zora kernel: wlan0: AP 00:25:9c:13:ac:90 changed bandwidth, new config is 5180 MHz, width 2 (5190/0 MHz)
Feb 26 14:19:01 zora kernel: wlan0: Limiting TX power to 17 (20 - 3) dBm as advertised by 00:25:9c:13:ac:90
On my WRT1900acs:
[ 1862.814018] ieee80211 phy0: radar detected by firmware
[ 1863.397854] ieee80211 phy0: channel switch is done
[ 1863.402676] ieee80211 phy0: change: 0x40
[ 1865.072518] ------------[ cut here ]------------
[ 1865.077211] WARNING: CPU: 1 PID: 1971 at compat-wireless-2016-10-08/net/mac80211/agg-tx.c:347 ___ieee80211_stop_tx_ba_session+0x134/0x1f8 [mac80211]()
[ 1865.090755] Modules linked in: iptable_nat nf_nat_ipv4 nf_conntrack_ipv6 nf_conntrack_ipv4 ipt_REJECT ipt_MASQUERADE xt_time xt_tcpudp xt_state xt_nat xt_multiport xt_mark xt_mac xt_limit xt_conntrack xt_comment xt_TCPMSS xt_REDIRECT xt_LOG nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache nf_conntrack iptable_mangle iptable_filter ip_tables crc_ccitt fuse mwlwifi mac80211 cfg80211 compat ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables nfsd nfsv3 nfs lockd sunrpc grace dm_crypt dm_mirror dm_region_hash dm_log dm_mod xts gf128mul sd_mod gpio_button_hotplug exportfs
[ 1865.152987] CPU: 1 PID: 1971 Comm: hostapd Not tainted 4.4.50 #0
[ 1865.159018] Hardware name: Marvell Armada 380/385 (Device Tree)
[ 1865.164970] [<c0027d80>] (unwind_backtrace) from [<c00244a4>] (show_stack+0x10/0x14)
[ 1865.172751] [<c00244a4>] (show_stack) from [<c021baec>] (dump_stack+0x8c/0xa0)
[ 1865.180006] [<c021baec>] (dump_stack) from [<c0034e74>] (warn_slowpath_common+0x94/0xb0)
[ 1865.188130] [<c0034e74>] (warn_slowpath_common) from [<c0034f2c>] (warn_slowpath_null+0x1c/0x24)
[ 1865.196971] [<c0034f2c>] (warn_slowpath_null) from [<bf158964>] (___ieee80211_stop_tx_ba_session+0x134/0x1f8 [mac80211])
[ 1865.207929] [<bf158964>] (___ieee80211_stop_tx_ba_session [mac80211]) from [<bf158e0c>] (__ieee80211_stop_tx_ba_session+0x2c/0x40 [mac80211])
[ 1865.220712] [<bf158e0c>] (__ieee80211_stop_tx_ba_session [mac80211]) from [<bf157a8c>] (ieee80211_sta_tear_down_BA_sessions+0x48/0x70 [mac80211])
[ 1865.233841] [<bf157a8c>] (ieee80211_sta_tear_down_BA_sessions [mac80211]) from [<bf14e8f4>] (ieee80211_sta_eosp+0x1dc/0x538 [mac80211])
[ 1865.246096] [<bf14e8f4>] (ieee80211_sta_eosp [mac80211]) from [<bf151ae8>] (__sta_info_destroy+0xc/0x28 [mac80211])
[ 1865.256608] [<bf151ae8>] (__sta_info_destroy [mac80211]) from [<bf151b74>] (sta_info_destroy_addr_bss+0x2c/0x44 [mac80211])
[ 1865.267816] [<bf151b74>] (sta_info_destroy_addr_bss [mac80211]) from [<bf114b60>] (nl80211_del_station+0xe8/0xf8 [cfg80211])
[ 1865.279096] [<bf114b60>] (nl80211_del_station [cfg80211]) from [<c03ce458>] (genl_rcv_msg+0x2dc/0x384)
[ 1865.288444] [<c03ce458>] (genl_rcv_msg) from [<c03cd778>] (netlink_rcv_skb+0x54/0xb4)
[ 1865.296307] [<c03cd778>] (netlink_rcv_skb) from [<c03ce170>] (genl_rcv+0x28/0x34)
[ 1865.303821] [<c03ce170>] (genl_rcv) from [<c03cd148>] (netlink_unicast+0x140/0x1f8)
[ 1865.311509] [<c03cd148>] (netlink_unicast) from [<c03cd588>] (netlink_sendmsg+0x2cc/0x340)
[ 1865.319811] [<c03cd588>] (netlink_sendmsg) from [<c038f474>] (sock_sendmsg+0x14/0x24)
[ 1865.327675] [<c038f474>] (sock_sendmsg) from [<c038fac0>] (___sys_sendmsg+0x20c/0x220)
[ 1865.335627] [<c038fac0>] (___sys_sendmsg) from [<c03908b8>] (__sys_sendmsg+0x3c/0x60)
[ 1865.343491] [<c03908b8>] (__sys_sendmsg) from [<c0009c80>] (ret_fast_syscall+0x0/0x3c)
[ 1865.351458] ---[ end trace c100057cae0d22d5 ]---