Since I upgraded from 17.01.4 to some recent snapshots I've noticed a problem with my wifi.
Several times in a day the wlan interfaces would get disabled and wouldn't restart without rebooting.
I checked the log and found a ton of kernel warnings and errors like
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.767297] ------------[ cut here ]------------
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.772174] WARNING: CPU: 1 PID: 61 at backports-2017-11-01/net/mac80211/driver-ops.c:39 ieee80211_del_virtual_monitor+0x7bc/0x7fc [mac80211]
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.776591] Modules linked in: pppoe ppp_async ath10k_pci ath10k_core ath pppox ppp_generic nf_conntrack_ipv6 mac80211 iptable_nat ipt_REJECT ipt_MASQUERADE cfg80211 xt_time xt_tcpudp xt_tcpmss xt_statistic xt_state xt_recent xt_nat xt_multiport xt_mark xt_mac xt_limit xt_length xt_hl xt_helper xt_ecn xt_dscp xt_conntrack xt_connmark xt_connlimit xt_connbytes xt_comment xt_TCPMSS xt_REDIRECT xt_LOG xt_HL xt_DSCP xt_CLASSIFY ums_usbat ums_sddr55 ums_sddr09 ums_karma ums_jumpshot ums_isd200 ums_freecom ums_datafab ums_cypress ums_alauda slhc nf_reject_ipv4 nf_nat_redirect nf_nat_masquerade_ipv4 nf_conntrack_ipv4 nf_nat_ipv4 nf_nat nf_log_ipv4 nf_defrag_ipv6 nf_defrag_ipv4 nf_conntrack_rtcache iptable_mangle iptable_filter ipt_ECN ip_tables crc_ccitt compat sch_cake nf_conntrack act_skbedit act_mirred
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.858517] em_u32 cls_u32 cls_tcindex cls_flow cls_route cls_fw sch_tbf sch_htb sch_hfsc sch_ingress ledtrig_usbport ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common ip6table_mangle ip6table_filter ip6_tables x_tables msdos ifb vfat fat ntfs nls_utf8 nls_iso8859_1 nls_cp437 usb_storage leds_gpio xhci_plat_hcd xhci_pci xhci_hcd dwc3 dwc3_of_simple uhci_hcd ohci_platform ohci_hcd phy_qcom_dwc3 ahci ehci_platform sd_mod ahci_platform libahci_platform libahci libata scsi_mod ehci_hcd gpio_button_hotplug ext4 jbd2 mbcache exfat crc32c_generic
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.906187] CPU: 1 PID: 61 Comm: kworker/1:1 Tainted: G W 4.9.67 #0
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.906444] Hardware name: Generic DT based system
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.914009] Workqueue: events_freezable ieee80211_restart_work [mac80211]
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.925048] [<c0215530>] (unwind_backtrace) from [<c0211f1c>] (show_stack+0x10/0x14)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.925386] [<c0211f1c>] (show_stack) from [<c0396ee8>] (dump_stack+0x7c/0x9c)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.933206] [<c0396ee8>] (dump_stack) from [<c021d844>] (__warn+0xbc/0xec)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.940233] [<c021d844>] (__warn) from [<c021d918>] (warn_slowpath_null+0x1c/0x24)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.947184] [<c021d918>] (warn_slowpath_null) from [<bf35ba24>] (ieee80211_del_virtual_monitor+0x7bc/0x7fc [mac80211])
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.954801] [<bf35ba24>] (ieee80211_del_virtual_monitor [mac80211]) from [<bf35ba74>] (ieee80211_stop+0x10/0x18 [mac80211])
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.965424] [<bf35ba74>] (ieee80211_stop [mac80211]) from [<c04f4ebc>] (__dev_close_many+0x94/0xb8)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.976352] [<c04f4ebc>] (__dev_close_many) from [<c04f4f40>] (dev_close_many+0x60/0xd4)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.985372] [<c04f4f40>] (dev_close_many) from [<c04f8a60>] (dev_close+0x30/0x48)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43466.993755] [<c04f8a60>] (dev_close) from [<bf30553c>] (cfg80211_shutdown_all_interfaces+0x64/0xb0 [cfg80211])
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.001208] [<bf30553c>] (cfg80211_shutdown_all_interfaces [cfg80211]) from [<bf374468>] (ieee80211_reconfig+0x334/0x9d4 [mac80211])
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.011141] [<bf374468>] (ieee80211_reconfig [mac80211]) from [<bf349190>] (ieee80211_restart_work+0x94/0xa8 [mac80211])
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.023139] [<bf349190>] (ieee80211_restart_work [mac80211]) from [<c02311fc>] (process_one_work+0x1d4/0x310)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.033900] [<c02311fc>] (process_one_work) from [<c0231f04>] (worker_thread+0x2ec/0x42c)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.043715] [<c0231f04>] (worker_thread) from [<c0235eb0>] (kthread+0xd8/0xec)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.051872] [<c0235eb0>] (kthread) from [<c020ec78>] (ret_from_fork+0x14/0x3c)
Mon Dec 11 16:42:00 2017 kern.warn kernel: [43467.059065] ---[ end trace 2a73b50fc0618784 ]---
Mon Dec 11 16:42:00 2017 kern.info kernel: [43467.066798] br-lan: port 3(wlan0) entered disabled state
Mon Dec 11 16:42:00 2017 daemon.notice netifd: Network device 'wlan0' link is down
since I upgraded to lede and openwrt 18.06.1 with my tp-link routers model (wdr4300, archer c5 and wr1043) I encounter a problem of disconnecting the wireless.