With ESPNow remote and no wifi WLED reboots every 15-20min

[hez]

What happened?

Without wifi to connect to the device is rebooting every 15-20min, if the AP it connects to is available then it appears to be stable over multiple days.

Runs fine on 14. As per #3685 (comment) this bug is being opened.

possibly related to: #3685

To Reproduce Bug

Connect the device to a wifi access point then turn off the AP.

Expected Behavior

Should be stable without wifi.

Install Method

Binary from WLED.me

What version of WLED?

WLED_16.0.0-beta_ESP32

Which microcontroller/board are you seeing the problem on?

ESP32

Relevant log/trace output

Anything else?

This is in a VERY isolated area, the wifi it connects to is literally the only wifi around.

It is paired with an ESPNow remote, but during the 15-20 before the reboot no buttons have been pressed.

Code of Conduct

• I agree to follow this project's Code of Conduct

[hez]

not sure if this is related: #5336 I will have to try disabling mdns

[softhack007]

@hez please also check if stability improves without the esp-now remote (remove it from settings).

[hez]

@hez please also check if stability improves without the esp-now remote (remove it from settings).

Without a wifi AP and no remote the lights will become very hard to control. 😬

[softhack007]

Yes, but it's a test. I want to know if esp-now freaks out without wifi connection (the esp-now service is still running even when you don't press buttons on your remote)

[hez]

@hez please also check if stability improves without the esp-now remote (remove it from settings).

I tested it a few times here and quite repeatedly with the ESPNow remote set it reboots.

• with ESPNow remote configured AND wifi: ✅
• with no ESPNow configured AND wifi: ✅
• with no ESPNow configured AND no wifi: ✅
• with ESPNow remote configured AND no wifi: 🛑 reboots every 15-20min

[softhack007]

Ok, managed to get a crash dump with the latest source code in main
the condition seems to be

• ESP-NOW enabled
• Wifi connection credential stored, but invalid (= WLED cannot connect to the network)

---DEBUG INFO---
Runtime: 1351891
Unix time: 1351,891
=== Memory Info ===
DRAM 8-bit:   Free:   26236 bytes | Largest block:    9716 bytes
DRAM 32-bit:  Free:   49356 bytes | Largest block: N/A
TX power: 60/78
Wifi state: 1
ESP-NOW state: 1
State time: 1351902
NTP last sync: 999000000
Client IP: 0.0.0.0
Loops/sec: 1499
Loop time[ms]: 0/76
UM time[ms]: 0/1
Strip time[ms]:0/2
Segments: 0 -> 0/0B
Modes: 4*220=880B
Data: 4*220=880B
Map: 2*0=0B
Web server status:  Idle
[1351925][E][WiFiUdp.cpp:251] endPacket(): could not send data: 118
Not connected AP (@ 1353s).
Opening access point WLED-AP
WiFi-E: AP Started
Init AP interfaces
[1354138][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1356995][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1359852][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Last reconnect (1341s) too old (@ 1359s).
initConnection() called @ 1359s.
ESP-NOW stopping.
WiFi-E: Event 3
getWLEDHostname: 'wled-9cef3c'
WiFi-E: AP Stopped
WiFi-E: Event 0
WiFi-E: Event 2
Access point disabled (init).
Connecting to WLAN233...
ESP-NOW initing in STA mode.
Not connected AP (@ 1359s).
Opening access point WLED-AP
WiFi-E: AP Started
Init AP interfaces
[1362877][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1365734][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1368591][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1371448][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1374304][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1377162][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Last reconnect (1360s) too old (@ 1378s).
initConnection() called @ 1378s.
ESP-NOW stopping.
WiFi-E: Event 3
getWLEDHostname: 'wled-9cef3c'
WiFi-E: AP Stopped
WiFi-E: Event 0
WiFi-E: Event 2
Access point disabled (init).
Connecting to WLAN233...
ESP-NOW initing in STA mode.
Not connected AP (@ 1378s).
Opening access point WLED-AP
WiFi-E: AP Started
Init AP interfaces
Local time: 00:23
[1380925][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
---DEBUG INFO---
Runtime: 1381924
Unix time: 1381,924
=== Memory Info ===
DRAM 8-bit:   Free:   19144 bytes | Largest block:    5108 bytes
DRAM 32-bit:  Free:   49356 bytes | Largest block: N/A
TX power: 60/78
Wifi state: 1
ESP-NOW state: 1
State time: 1351902
NTP last sync: 999000000
Client IP: 0.0.0.0
Loops/sec: 1365
Loop time[ms]: 0/75
UM time[ms]: 0/1
Strip time[ms]:0/2
Segments: 0 -> 0/0B
Modes: 4*220=880B
Data: 4*220=880B
Map: 2*0=0B
Web server status:  Idle
[1383784][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1386642][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1389501][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1392359][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1395216][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Last reconnect (1378s) too old (@ 1396s).
initConnection() called @ 1396s.
ESP-NOW stopping.
WiFi-E: Event 3
getWLEDHostname: 'wled-9cef3c'
WiFi-E: AP Stopped
WiFi-E: Event 0
WiFi-E: Event 2
Access point disabled (init).
Connecting to WLAN233...
ESP-NOW initing in STA mode.
Not connected AP (@ 1396s).
Opening access point WLED-AP
WiFi-E: AP Started
Init AP interfaces
[1398977][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Loop delayed more than 8ms.
[1401835][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1404692][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1407549][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1410406][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
---DEBUG INFO---
Runtime: 1411957
Unix time: 1411,957
=== Memory Info ===
DRAM 8-bit:   Free:   26444 bytes | Largest block:    8180 bytes
DRAM 32-bit:  Free:   49356 bytes | Largest block: N/A
TX power: 60/78
Wifi state: 1
ESP-NOW state: 1
State time: 1351902
NTP last sync: 999000000
Client IP: 0.0.0.0
Loops/sec: 1329
Loop time[ms]: 0/76
UM time[ms]: 0/1
Strip time[ms]:0/2
Segments: 0 -> 0/0B
Modes: 4*220=880B
Data: 4*220=880B
Map: 2*0=0B
Web server status:  Idle
[1413263][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Last reconnect (1396s) too old (@ 1414s).
initConnection() called @ 1414s.
ESP-NOW stopping.
Guru Meditation Error: Core  1 panic'ed (StoreProhibited). Exception was unhandled.
Core  1 register dump:
PC      : 0x4008ec9b  PS      : 0x00060333  A0      : 0x801cba1e  A1      : 0x3ffb1f50  
A2      : 0x3fff9af4  A3      : 0x3ffcdee8  A4      : 0x3ffcdeec  A5      : 0x0000abab  
A6      : 0x00060323  A7      : 0x00060320  A8      : 0xffffffff  A9      : 0x00000000  
A10     : 0x3fff9b40  A11     : 0x3f404931  A12     : 0x00000011  A13     : 0x0000ff00  
A14     : 0x003fffff  A15     : 0xff000000  SAR     : 0x0000001f  EXCCAUSE: 0x0000001d  
EXCVADDR: 0x00000004  LBEG    : 0x4008c685  LEND    : 0x4008c695  LCOUNT  : 0xfffffffb  
Backtrace: 0x4008ec98:0x3ffb1f50 0x401cba1b:0x3ffb1f70 0x4013d259:0x3ffb1f90 0x40121f5a:0x3ffb1fb0 0x401223a2:0x3ffb20d0 0x4012258c:0x3ffb21c0 0x40122bda:0x3ffb2270 0x4014522d:0x3ffb2290
ELF file SHA256: 2c2b1eb2f530cf5d
Rebooting...
ets Jul 29 2019 12:21:46
rst:0xc (SW_CPU_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0030,len:184
load:0x40078000,len:12732
ho 0 tail 12 room 4
load:0x40080400,len:2908
entry 0x400805c4
---WLED 17.0.0-dev 2605011 INIT---
esp32 4.4.8.240628
arduino-esp32 v2.0.17
CPU:   ESP32-D0WD-V3 rev.3, 2 core(s), 240 MHz.
FLASH: 4 MB, Mode 2 (DIO), speed 40 MHz.
heap 214240
[    48][W][WiFiGeneric.cpp:1413] getTxPower(): Neither AP or STA has been started
TX power: 78/78
PIN ALLOC: Pin 1 successfully allocated by 0x89.
PIN ALLOC: 0x0000000000000lX.
heap 214240
checking for bootloop: time 72, counter 0, action 0
crash detected!
Valid JSON file /cfg.json
Reading config
Reading settings from /wsec.json...
JSON buffer locked. (3)
JSON buffer released. (3)
JSON buffer locked. (1)
Reading settings from /cfg.json...
Heap before buses: 211996
PIN ALLOC: Pin 0 successfully allocated by 0x85.
PIN ALLOC: 0x0000000000000lX.
All timers cleared
Starting usermod config.
JSON buffer released. (1)
heap 211864
Initializing strip

StoreProhibited (Exception 29: Access to invalid address: STORE (wild pointer?))
Core: 1
PC: 0x4008ec9b
Fault Address: 0x00000004
Fault Code: 29

Address	Function	Location
0x4008ec98	uxListRemove	list.c:190
0x401cba1b	vTaskDelete	tasks.c:1345
0x4013d259	QuickEspNow::stop()	QuickEspNow_esp32.cpp:55
0x40121f5a	WLED::initConnection()	wled.cpp:689
0x401223a2	WLED::handleConnection()	wled.cpp:941
0x4012258c	WLED::loop()	wled.cpp:64
0x40122bda	loop()	wled_main.cpp:23
0x4014522d	loopTask(void*)	main.cpp:50

The crash is inside the QickEspNow external library:

void QuickEspNow::stop () {
    DEBUG_INFO (QESPNOW_TAG, "-------------> ESP-NOW STOP");
    vTaskDelete (espnowTxTask); /// <<----- crash is HERE
    vTaskDelete (espnowRxTask);
    esp_now_unregister_recv_cb ();
    esp_now_unregister_send_cb ();
    esp_now_deinit ();
}

[softhack007]

@coderabbitai please review the main repo of QuickEspNow for known problems with frequent start/stop in AP mode. We are using this fork of the library https://github.com/blazoncek/QuickESPNow.git#optional-debug. Also check the debug output above (WLED_DEBUG + CORE_DEBUG_LEVEL=1) for "smoking guns" that might help explain the problem.

[coderabbitai]

@softhack007 — here's a thorough analysis of the crash and the upstream library's known problems:

---

Root Cause Analysis

The Crash

The StoreProhibited exception at EXCVADDR: 0x00000004 inside uxListRemove is a classic stale/dangling TaskHandle_t crash. At offset 4 of a FreeRTOS TCB lies the xStateListItem member; writing to it means the TCB was already freed (the task deleted itself or was already deleted), but espnowTxTask still holds the old pointer.

The call chain is:

vTaskDelete(espnowTxTask)  →  uxListRemove(&tcb->xStateListItem)
                                            ^^^^ TCB already freed → crash

Smoking Guns in the Debug Log

1. Memory leak per stop/start cycle:

   • At t=1351s: free DRAM = 26 236 bytes
   • At t=1381s: free DRAM = 19 144 bytes (−7 KB in 30 s)
   • At t=1411s: free DRAM = 26 444 bytes (recovers slightly — but the leak is real and cumulative across longer runs)
   • This matches the pattern of xTaskCreate allocating stack+TCB on each begin(), and vTaskDelete on a stale handle not actually freeing anything — the stack of the previously created task leaks.

2. Rapid stop/start cycling (~every 18 s):

   ESP-NOW stopping.
   ... (WiFi init) ...
   ESP-NOW initing in STA mode.
   

   WLED calls initConnection() roughly every 18 s when the configured WiFi AP is unreachable. Each cycle triggers a stop()→begin() pair.

3. espnowTxTask handle is never reset to NULL:
   If begin() fails part-way through (e.g. xTaskCreate returns an error because there's not enough heap), espnowTxTask retains its old stale value from the previous successful begin(). The next stop() then passes this dangling pointer to vTaskDelete().

Known Issue in the Upstream Library

Repeating FreeRTOS task creation and deletion without a pause is known to crash the ESP32 FreeRTOS implementation. Adding a pause of at least 3 ticks after vTaskDelete is required for safe operation.

A TaskHandle_t is a pointer to an internal task structure; when vTaskDelete is called, that structure is freed — meaning the handle now points to effectively uninitialized memory, and any further operation on it is undefined.

The upstream gmag11/QuickESPNow stop() function has no guard against:

• Calling vTaskDelete on an already-deleted handle
• Calling vTaskDelete on a NULL handle (from a failed xTaskCreate)
• Leaving handles non-NULL after deletion

The Fix

The QuickEspNow::stop() in the fork needs at minimum:

void QuickEspNow::stop () {
    DEBUG_INFO (QESPNOW_TAG, "-------------> ESP-NOW STOP");
    if (espnowTxTask) {
        vTaskDelete (espnowTxTask);
        espnowTxTask = nullptr;   // ← MUST reset to avoid dangling handle
    }
    if (espnowRxTask) {
        vTaskDelete (espnowRxTask);
        espnowRxTask = nullptr;
    }
    esp_now_unregister_recv_cb ();
    esp_now_unregister_send_cb ();
    esp_now_deinit ();
}

And begin() / start() must also set handles to nullptr before xTaskCreate, and check the return value:

espnowTxTask = nullptr;  // clear before create
if (xTaskCreate(..., &espnowTxTask, ...) != pdPASS) {
    // handle error — do not proceed
}

Recommendation

It would be worth:

1. Patching the fork (blazoncek/QuickESPNow) with the NULL-guards above.
2. Reducing the stop/start frequency on WLED's side — e.g. avoid restarting ESP-NOW if it was already stopped, or add a minimum interval between initConnection() calls when the AP is known to be unreachable.
3. Checking the begin() return value in WLED's ESP-NOW init code and skipping stop() if begin() never succeeded.

[softhack007]

more problems .... i've added nullptr checks into the library (my own local copy), but now the crash is just in another location

---DEBUG INFO---
Runtime: 1261737
Unix time: 1261,737
=== Memory Info ===
DRAM 8-bit:   Free:   32592 bytes | Largest block:   10228 bytes
DRAM 32-bit:  Free:   49356 bytes | Largest block: N/A
TX power: 61/78
Wifi state: 1
ESP-NOW state: 1
State time: 1261748

Opening access point WLED-AP
WiFi-E: AP Started
Init AP interfaces
Local time: 00:23
[1381027][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
---DEBUG INFO---
Runtime: 1381865
Unix time: 1381,865
=== Memory Info ===
DRAM 8-bit:   Free:   19156 bytes | Largest block:     404 bytes
DRAM 32-bit:  Free:   49356 bytes | Largest block: N/A
TX power: 61/78
Wifi state: 1
ESP-NOW state: 1
State time: 1261748
NTP last sync: 999000000
Client IP: 0.0.0.0
Loops/sec: 1327
Loop time[ms]: 0/78
UM time[ms]: 0/1
Strip time[ms]:0/9
Segments: 0 -> 0/0B
Modes: 4*220=880B
Data: 4*220=880B
Map: 2*0=0B
Web server status: print buffer failure
[1383885][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1386743][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1389599][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1392456][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
[1395312][W][WiFiGeneric.cpp:1058] _eventCallback(): Reason: 201 - NO_AP_FOUND
Last reconnect (1378s) too old (@ 1396s).
initConnection() called @ 1396s.
ESP-NOW stopping.
WiFi-E: Event 3
getWLEDHostname: 'wled-9cef3c'
WiFi-E: AP Stopped
WiFi-E: Event 0
WiFi-E: Event 2
Access point disabled (init).
Connecting to WLAN233...
ESP-NOW initing in STA mode.
Not connected AP (@ 1396s).
Opening access point WLED-AP

Guru Meditation Error: Core  0 panic'ed (LoadProhibited). Exception was unhandled.

Core  0 register dump:
PC      : 0x4018c3a5  PS      : 0x00060730  A0      : 0x8018dbd6  A1      : 0x3ffbbff0  
A2      : 0x00000000  A3      : 0x3ffcedd4  A4      : 0x3ffd02d8  A5      : 0x00000000  
A6      : 0x3fffcba8  A7      : 0x00000001  A8      : 0x8018c39d  A9      : 0x3ffbbf80  
A10     : 0x3ffbe680  A11     : 0x3ffc0ed4  A12     : 0x00000002  A13     : 0x3f43ab65  
A14     : 0x00000000  A15     : 0x00000000  SAR     : 0x0000001b  EXCCAUSE: 0x0000001c  
EXCVADDR: 0x0000002c  LBEG    : 0x4008b8f9  LEND    : 0x4008b91b  LCOUNT  : 0xffffffff  


Backtrace: 0x4018c3a2:0x3ffbbff0 0x4018dbd3:0x3ffbc050 0x40191b89:0x3ffbc080 0x40192d3c:0x3ffbc0a0 0x401915f0:0x3ffbc0d0 0x401c6b99:0x3ffbc0f0

#	Address	Function	Location
0	0x4018c3a2	ieee80211_hostap_attach	??
1	0x4018dbd3	wifi_softap_start	??
2	0x40191b89	_do_wifi_start	??
3	0x40192d3c	wifi_set_mode_process	??
4	0x401915f0	ieee80211_ioctl_process	??
5	0x401c6b99	ppTask	??

The DRAM decrease is unusual 🤔 We know that any ESP32 will get unstable if the smallest HEAP chunk is less than 10Kb.

[softhack007]

@coderabbitai every call of QuickEspNow::begin() seems to create two new FreeRTOS queues, but I did not see where these queuey would be deleted in QuickEspNow::end(). Please check if this might explain the RAM decrease over time.

https://github.com/blazoncek/QuickESPNow/blob/193e991642cbffe1d44e7445a0a34445f69a67d8/src/QuickEspNow_esp32.cpp#L317