[3.3.7][ESP32-S3][BLE] TLSF assert on BLE startup (block_locate_free) on XIAO ESP32S3; 3.3.6 works

[TideGear]

Board

XIAO_ESP32S3 (Seeed Studio XIAO ESP32S3)

Device Description

Seeed XIAO ESP32S3 running a BLE HID sketch (NimBLE + ESP32-BLE-CompositeHID).

Hardware Configuration

I2C devices attached: SSD1306 OLED on GPIO5/6 and LTR390 UV sensor on GPIO5/6. Push button on GPIO1. Optional battery sense divider on GPIO2.
Issue reproduces specifically when BLE is enabled.

Version

v3.3.7

Type

Bug

IDE Name

Arduino IDE 2.3.7

Operating System

Windows 10 (10.0.19045)

Flash frequency

80

PSRAM enabled

no

Upload speed

921600

Description

After updating Arduino ESP32 core from 3.3.6 to 3.3.7, BLE startup crashes reliably on Seeed XIAO ESP32S3 with:

assert failed: block_locate_free tlsf_control_functions.h:618 (block_size(block) >= *size)

Behavior is deterministic. Rolling back to 3.3.6 fixes the issue immediately with the same hardware, wiring, and sketch.

Expected:
BLE initializes normally and device runs.

Actual:
Device asserts/reboots during BLE bring-up.

Sketch

https://github.com/TideGear/BoktaiSensor

Debug Message

btdm: bss start 0x3fcef180, len 36
btdm: data start 0x3fcef174, data start rom 0x40057350, len 12
MAGIC fadebead VERSION 0001000a
MAGIC fadebead VERSION 00010001

assert failed: block_locate_free tlsf_control_functions.h:618 (block_size(block) >= *size)

Backtrace: 0x4038161d:0x3fcae150 0x403815e5:0x3fcae170 0x40387ba6:0x3fcae190 ...
ELF file SHA256: 7e6dd08ea
Rebooting...

Other Steps to Reproduce

1. Install esp32 core 3.3.7 in Arduino IDE.
2. Select XIAO_ESP32S3 and upload BLE-enabled sketch.
3. Open Serial Monitor at 115200.
4. Observe immediate TLSF assert during BLE startup.

Control test:

• Same exact setup + core 3.3.6 -> no crash.

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[lucasssvaz]

Can't reproduce the issue with the Server_Gamepad example:

ESP-ROM:esp32s3-20210327
Build:Mar 27 2021
rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)
SPIWP:0xee
mode:DIO, clock div:1
load:0x3fce2820,len:0x10cc
load:0x403c8700,len:0xc2c
load:0x403cb700,len:0x30c0
entry 0x403c88b8
Starting BLE HID Gamepad
BLE HID Gamepad ready!
Waiting for connection...

Please add a minimum reproducible sketch of this issue.

[TideGear]

#include <BleCompositeHID.h>
#include <XboxGamepadDevice.h>
#include <XboxGamepadConfiguration.h>

BleCompositeHID hid("TestPad", "Espressif", 100);
XboxGamepadDevice* gamepad = nullptr;

void setup() {
  Serial.begin(115200);
  delay(500);
  Serial.println("Starting BLE HID Gamepad...");

  auto* cfg = new XboxSeriesXControllerDeviceConfiguration();
  BLEHostConfiguration host = cfg->getIdealHostConfiguration();

  gamepad = new XboxGamepadDevice(cfg);
  hid.addDevice(gamepad);
  hid.begin(host);  // crash point on esp32 core 3.3.7

  Serial.println("BLE HID Gamepad ready!");
}

void loop() {
  delay(1000);
}

[lucasssvaz]

I can see that this library does not use our BLE API. I cannot help as I don't know the source code.
Please open an issue in the library repository.

[farzadh86]

ESP32-C3 BLE crash on Arduino Core 3.3.7 – works fine on 3.3.6

Hello,

After updating Arduino-ESP32 to version 3.3.7, my project using BLE + FreeRTOS + PWM on ESP32-C3 started crashing with:

Guru Meditation Error: Core 0 panic'ed (Store access fault)
MCAUSE: 7
MTVAL: 0x00000070

The crash appears immediately when BLE is enabled.
Everything works perfectly on 3.3.6, with no changes in hardware or code.

I tested:

• Different power sources (USB, AC-DC SMPS)
• No external peripherals
• Minimal BLE examples
• PWM disabled/enabled
• Clean install of the platform

The crash only happens on v3.3.7 and disappears after downgrading to 3.3.6.

This seems to be a BLE stack regression in version 3.3.7 specifically for ESP32-C3.

[TideGear]

Reopening for farzadh

[lucasssvaz]

@farzadh86 Please open a new issue with the steps to reproduce it.