I just got the WiFi crash.
Login via LAN is possible. The Web Gui shows:
Memory
Total Available
5736 kB / 27844 kB (20%)
Free
3504 kB / 27844 kB (12%)
Buffered
2232 kB / 27844 kB (8%)
System log (crash happened around 22:30):
Thu Aug 1 22:00:32 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:07:37 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:14:35 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:16:45 2019 daemon.info hostapd: wlan0: STA fc:a6:67:c6:9f:af IEEE 802.11: authenticated
Thu Aug 1 22:16:45 2019 daemon.info hostapd: wlan0: STA fc:a6:67:c6:9f:af IEEE 802.11: associated (aid 10)
Thu Aug 1 22:16:46 2019 daemon.notice hostapd: wlan0: AP-STA-CONNECTED fc:a6:67:c6:9f:af
Thu Aug 1 22:16:46 2019 daemon.info hostapd: wlan0: STA fc:a6:67:c6:9f:af WPA: pairwise key handshake completed (RSN)
Thu Aug 1 22:16:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPDISCOVER(br-lan) fc:a6:67:c6:9f:af
Thu Aug 1 22:16:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPOFFER(br-lan) 192.168.1.112 fc:a6:67:c6:9f:af
Thu Aug 1 22:16:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPREQUEST(br-lan) 192.168.1.112 fc:a6:67:c6:9f:af
Thu Aug 1 22:16:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPACK(br-lan) 192.168.1.112 fc:a6:67:c6:9f:af fire-tv-stick
Thu Aug 1 22:16:48 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:17:48 2019 daemon.info dnsmasq-dhcp[1397]: DHCPREQUEST(br-lan) 192.168.1.106 00:25:dc:ee:e1:32
Thu Aug 1 22:17:48 2019 daemon.info dnsmasq-dhcp[1397]: DHCPACK(br-lan) 192.168.1.106 00:25:dc:ee:e1:32 qivicon-home-base
Thu Aug 1 22:18:06 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:22:51 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:22:52 2019 daemon.info dnsmasq-dhcp[1397]: DHCPREQUEST(br-lan) 192.168.1.106 00:25:dc:ee:e1:32
Thu Aug 1 22:22:52 2019 daemon.info dnsmasq-dhcp[1397]: DHCPACK(br-lan) 192.168.1.106 00:25:dc:ee:e1:32 qivicon-home-base
Thu Aug 1 22:26:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPREQUEST(br-lan) 192.168.1.106 00:25:dc:ee:e1:32
Thu Aug 1 22:26:47 2019 daemon.info dnsmasq-dhcp[1397]: DHCPACK(br-lan) 192.168.1.106 00:25:dc:ee:e1:32 qivicon-home-base
Thu Aug 1 22:28:51 2019 daemon.info odhcpd[849]: Using a RA lifetime of 0 seconds on br-lan
Thu Aug 1 22:29:34 2019 daemon.info hostapd: wlan0: STA fc:a6:67:c6:9f:af IEEE 802.11: disconnected due to excessive missing ACKs
Thu Aug 1 22:29:34 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED fc:a6:67:c6:9f:af
Thu Aug 1 22:30:04 2019 daemon.info hostapd: wlan0: STA fc:a6:67:c6:9f:af IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:31:16 2019 daemon.err uhttpd[904]: luci: accepted login on / for root from fdd5:24c4:abb4::e078:4761:e611:2310
Thu Aug 1 22:34:03 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 40:31:3c:a4:6f:cb
Thu Aug 1 22:34:03 2019 daemon.info hostapd: wlan0: STA 40:31:3c:a4:6f:cb IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:04 2019 daemon.info hostapd: wlan0: STA 40:31:3c:a4:6f:cb IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:15 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 1c:12:b0:e0:93:0d
Thu Aug 1 22:34:15 2019 daemon.info hostapd: wlan0: STA 1c:12:b0:e0:93:0d IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:16 2019 daemon.info hostapd: wlan0: STA 1c:12:b0:e0:93:0d IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:17 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 3c:bd:3e:57:ee:c1
Thu Aug 1 22:34:17 2019 daemon.info hostapd: wlan0: STA 3c:bd:3e:57:ee:c1 IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:18 2019 daemon.info hostapd: wlan0: STA 3c:bd:3e:57:ee:c1 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:18 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 7c:49:eb:15:66:bd
Thu Aug 1 22:34:18 2019 daemon.info hostapd: wlan0: STA 7c:49:eb:15:66:bd IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:19 2019 daemon.info hostapd: wlan0: STA 7c:49:eb:15:66:bd IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:19 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 68:54:fd:e6:c3:c8
Thu Aug 1 22:34:19 2019 daemon.info hostapd: wlan0: STA 68:54:fd:e6:c3:c8 IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:20 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 5c:ff:ff:9f:2d:91
Thu Aug 1 22:34:20 2019 daemon.info hostapd: wlan0: STA 5c:ff:ff:9f:2d:91 IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:20 2019 daemon.info hostapd: wlan0: STA 68:54:fd:e6:c3:c8 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:21 2019 daemon.info hostapd: wlan0: STA 5c:ff:ff:9f:2d:91 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:28 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 48:d6:d5:6a:85:66
Thu Aug 1 22:34:28 2019 daemon.info hostapd: wlan0: STA 48:d6:d5:6a:85:66 IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:29 2019 daemon.info hostapd: wlan0: STA 48:d6:d5:6a:85:66 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:31 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED f0:d7:aa:00:7e:9d
Thu Aug 1 22:34:31 2019 daemon.info hostapd: wlan0: STA f0:d7:aa:00:7e:9d IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:32 2019 daemon.info hostapd: wlan0: STA f0:d7:aa:00:7e:9d IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Thu Aug 1 22:34:35 2019 daemon.notice hostapd: wlan0: AP-STA-DISCONNECTED 34:ea:34:f4:3c:42
Thu Aug 1 22:34:35 2019 daemon.info hostapd: wlan0: STA 34:ea:34:f4:3c:42 IEEE 802.11: disassociated due to inactivity
Thu Aug 1 22:34:36 2019 daemon.info hostapd: wlan0: STA 34:ea:34:f4:3c:42 IEEE 802.11: deauthenticated due to inactivity (timer DEAUTH/REMOVE)
Entire Kernel log (not sure whether anything relevant happened here, because there is no real timestamp):
[ 0.000000] Linux version 4.9.184 (buildbot@2ccc8102e0c3) (gcc version 7.3.0 (OpenWrt GCC 7.3.0 r7808-ef686b7292) ) #0 Thu Jun 27 12:18:52 2019
[ 0.000000] MyLoader: sysp=aaaba2aa, boardp=a2aaaaa2, parts=2aaa2a2a
[ 0.000000] bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 00019374 (MIPS 24Kc)
[ 0.000000] SoC: Qualcomm Atheros QCA9533 ver 1 rev 1
[ 0.000000] Determined physical RAM map:
[ 0.000000] memory: 02000000 @ 00000000 (usable)
[ 0.000000] Initrd not found or empty - disabling initrd
[ 0.000000] Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
[ 0.000000] Primary data cache 32kB, 4-way, VIPT, cache aliases, linesize 32 bytes
[ 0.000000] Zone ranges:
[ 0.000000] Normal [mem 0x0000000000000000-0x0000000001ffffff]
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000000000000-0x0000000001ffffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x0000000001ffffff]
[ 0.000000] On node 0 totalpages: 8192
[ 0.000000] free_area_init_node: node 0, pgdat 80440ac4, node_mem_map 81000020
[ 0.000000] Normal zone: 64 pages used for memmap
[ 0.000000] Normal zone: 0 pages reserved
[ 0.000000] Normal zone: 8192 pages, LIFO batch:0
[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
[ 0.000000] pcpu-alloc: [0] 0
[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 8128
[ 0.000000] Kernel command line: board=TL-WR841N-v9 console=ttyS0,115200 rootfstype=squashfs noinitrd
[ 0.000000] PID hash table entries: 128 (order: -3, 512 bytes)
[ 0.000000] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.000000] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.000000] Writing ErrCtl register=00000000
[ 0.000000] Readback ErrCtl register=00000000
[ 0.000000] Memory: 27604K/32768K available (3389K kernel code, 162K rwdata, 424K rodata, 240K init, 211K bss, 5164K reserved, 0K cma-reserved)
[ 0.000000] SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.000000] NR_IRQS:51
[ 0.000000] Clocks: CPU:550.000MHz, DDR:395.800MHz, AHB:197.900MHz, Ref:25.000MHz
[ 0.000000] clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 6950037990 ns
[ 0.000010] sched_clock: 32 bits at 275MHz, resolution 3ns, wraps every 7809031678ns
[ 0.008274] Calibrating delay loop... 366.18 BogoMIPS (lpj=1830912)
[ 0.071070] pid_max: default: 32768 minimum: 301
[ 0.076075] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.083063] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.093839] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
[ 0.104265] futex hash table entries: 256 (order: -1, 3072 bytes)
[ 0.112200] NET: Registered protocol family 16
[ 0.118661] MIPS: machine is TP-LINK TL-WR841N/ND v9
[ 0.614346] clocksource: Switched to clocksource MIPS
[ 0.620969] NET: Registered protocol family 2
[ 0.626708] TCP established hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.634071] TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
[ 0.640848] TCP: Hash tables configured (established 1024 bind 1024)
[ 0.647698] UDP hash table entries: 256 (order: 0, 4096 bytes)
[ 0.653876] UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
[ 0.660844] NET: Registered protocol family 1
[ 0.665520] PCI: CLS 0 bytes, default 32
[ 0.669767] Crashlog allocated RAM at address 0x1f00000
[ 0.676720] workingset: timestamp_bits=30 max_order=13 bucket_order=0
[ 0.691427] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 0.697629] jffs2: version 2.2 (NAND) (SUMMARY) (LZMA) (RTIME) (CMODE_PRIORITY) (c) 2001-2006 Red Hat, Inc.
[ 0.719014] io scheduler noop registered
[ 0.723152] io scheduler deadline registered (default)
[ 0.729116] Serial: 8250/16550 driver, 16 ports, IRQ sharing enabled
[ 0.738909] console [ttyS0] disabled
[ 0.762857] serial8250.0: ttyS0 at MMIO 0x18020000 (irq = 11, base_baud = 1562500) is a 16550A
[ 0.771974] console [ttyS0] enabled
[ 0.779540] bootconsole [early0] disabled
[ 0.795431] m25p80 spi0.0: found s25sl032p, expected m25p80
[ 0.801217] m25p80 spi0.0: s25sl032p (4096 Kbytes)
[ 0.807149] 5 tp-link partitions found on MTD device spi0.0
[ 0.812916] Creating 5 MTD partitions on "spi0.0":
[ 0.817934] 0x000000000000-0x000000020000 : "u-boot"
[ 0.825422] 0x000000020000-0x00000016babc : "kernel"
[ 0.832952] 0x00000016babc-0x0000003f0000 : "rootfs"
[ 0.840019] mtd: device 2 (rootfs) set to be root filesystem
[ 0.846007] 1 squashfs-split partitions found on MTD device rootfs
[ 0.852398] 0x0000003a0000-0x0000003f0000 : "rootfs_data"
[ 0.860553] 0x0000003f0000-0x000000400000 : "art"
[ 0.867900] 0x000000020000-0x0000003f0000 : "firmware"
[ 0.876841] libphy: Fixed MDIO Bus: probed
[ 0.906899] libphy: ag71xx_mdio: probed
[ 1.536909] ag71xx-mdio.1: Found an AR934X built-in switch
[ 1.590359] eth0: Atheros AG71xx at 0xba000000, irq 5, mode:GMII
[ 2.227319] ag71xx ag71xx.0: connected to PHY at ag71xx-mdio.1:04 [uid=004dd042, driver=Generic PHY]
[ 2.237626] eth1: Atheros AG71xx at 0xb9000000, irq 4, mode:MII
[ 2.246303] NET: Registered protocol family 10
[ 2.256180] NET: Registered protocol family 17
[ 2.260840] bridge: filtering via arp/ip/ip6tables is no longer available by default. Update your scripts to load br_netfilter if you need this.
[ 2.274418] 8021q: 802.1Q VLAN Support v1.8
[ 2.280825] hctosys: unable to open rtc device (rtc0)
[ 2.291491] VFS: Mounted root (squashfs filesystem) readonly on device 31:2.
[ 2.300486] Freeing unused kernel memory: 240K
[ 2.305117] This architecture does not have kernel memory protection.
[ 2.534402] random: fast init done
[ 3.036909] init: Console is alive
[ 3.040701] init: - watchdog -
[ 3.955214] kmodloader: loading kernel modules from /etc/modules-boot.d/*
[ 4.015124] kmodloader: done loading kernel modules from /etc/modules-boot.d/*
[ 4.033524] init: - preinit -
[ 4.822752] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 4.854021] random: procd: uninitialized urandom read (4 bytes read)
[ 6.455796] eth0: link up (1000Mbps/Full duplex)
[ 6.460611] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 8.154188] jffs2: notice: (401) jffs2_build_xattr_subsystem: complete building xattr subsystem, 0 of xdatum (0 unchecked, 0 orphan) and 0 of xref (0 dead, 0 orphan) found.
[ 8.171832] mount_root: switching to jffs2 overlay
[ 8.215749] urandom-seed: Seeding with /etc/urandom.seed
[ 8.421336] eth0: link down
[ 8.438610] procd: - early -
[ 8.441717] procd: - watchdog -
[ 9.082657] procd: - watchdog -
[ 9.086372] procd: - ubus -
[ 9.199434] random: ubusd: uninitialized urandom read (4 bytes read)
[ 9.208936] random: ubusd: uninitialized urandom read (4 bytes read)
[ 9.216118] random: ubusd: uninitialized urandom read (4 bytes read)
[ 9.223686] procd: - init -
[ 9.648216] kmodloader: loading kernel modules from /etc/modules.d/*
[ 9.660002] ip6_tables: (C) 2000-2006 Netfilter Core Team
[ 9.678493] Loading modules backported from Linux version wt-2017-11-01-0-gfe248fc2c180
[ 9.686850] Backport generated by backports.git v4.14-rc2-1-31-g86cf0e5d
[ 9.697430] ip_tables: (C) 2000-2006 Netfilter Core Team
[ 9.712666] nf_conntrack version 0.5.0 (1024 buckets, 4096 max)
[ 9.781873] xt_time: kernel timezone is -0000
[ 9.846352] PPP generic driver version 2.4.2
[ 9.853706] NET: Registered protocol family 24
[ 9.904147] ath: EEPROM regdomain: 0x0
[ 9.904159] ath: EEPROM indicates default country code should be used
[ 9.904163] ath: doing EEPROM country->regdmn map search
[ 9.904182] ath: country maps to regdmn code: 0x3a
[ 9.904188] ath: Country alpha2 being used: US
[ 9.904192] ath: Regpair used: 0x3a
[ 9.916189] ieee80211 phy0: Selected rate control algorithm 'minstrel_ht'
[ 9.921223] ieee80211 phy0: Atheros AR9531 Rev:1 mem=0xb8100000, irq=47
[ 10.045790] kmodloader: done loading kernel modules from /etc/modules.d/*
[ 11.207728] urandom_read: 5 callbacks suppressed
[ 11.207738] random: jshn: uninitialized urandom read (4 bytes read)
[ 21.940359] br-lan: port 1(eth0) entered blocking state
[ 21.945846] br-lan: port 1(eth0) entered disabled state
[ 21.951695] device eth0 entered promiscuous mode
[ 22.039213] IPv6: ADDRCONF(NETDEV_UP): br-lan: link is not ready
[ 22.109178] IPv6: ADDRCONF(NETDEV_UP): eth1: link is not ready
[ 23.573474] eth0: link up (1000Mbps/Full duplex)
[ 23.671762] br-lan: port 1(eth0) entered blocking state
[ 23.677245] br-lan: port 1(eth0) entered forwarding state
[ 23.754438] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
[ 24.227233] eth1: link up (100Mbps/Full duplex)
[ 24.274508] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready
[ 24.356682] ath: EEPROM regdomain: 0x8114
[ 24.360838] ath: EEPROM indicates we should expect a country code
[ 24.367206] ath: doing EEPROM country->regdmn map search
[ 24.372690] ath: country maps to regdmn code: 0x37
[ 24.377654] ath: Country alpha2 being used: DE
[ 24.382240] ath: Regpair used: 0x37
[ 24.385859] ath: regdomain 0x8114 dynamically updated by user
[ 27.395802] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[ 27.498877] br-lan: port 2(wlan0) entered blocking state
[ 27.504464] br-lan: port 2(wlan0) entered disabled state
[ 27.510437] device wlan0 entered promiscuous mode
[ 28.228312] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[ 28.235326] br-lan: port 2(wlan0) entered blocking state
[ 28.240852] br-lan: port 2(wlan0) entered forwarding state
[ 49.106789] random: crng init done
Do you see anything that might give a clue on what has happened?