Simultaneous use of LitteleFS and USBSerial

[MC-YasuhiroHirano]

Hello, thanks for this useful software !
I'm using rp2040 with platformio.
Also, I'm using FreeRTOS.

I want to write files using LitteleFS and keyboard input using USB serial asynchronously.
However, when I try to perform this process, the program stuck on keyboard input.
I tried it in the main loop of core0 instead of asynchronous and it stuck as well.

Paste MCVE.

#include <Arduino.h>
#include <FreeRTOS.h>
#include <LittleFS.h>

int cnt;

void setup() {
  Serial.begin(115200, true);
  cnt = 0;
  LittleFS.begin();
}

void loop() {
  char buf[64] = {0};
  File _lfs;
  int ret = 0;
  char c;
  delay(10);
  
  cnt++;
  if(!(cnt % 100))
  {
    sprintf(buf,"cnt[%d]\r\n",cnt);
    Serial.printf(buf);
    _lfs = LittleFS.open("/logfile.log", "a");
    if(_lfs){
      ret = _lfs.write(buf,strlen(buf));
    }
    _lfs.close();
  }

  while(Serial.available()>0) {
    c = Serial.read();
    Serial.print(c);
  }
}

MCVE only writes files periodically.

Please run MCVE, connect the USB cable and repeat keyboard input through the COM port.
The program will stuck.

• It will not stuck without keyboard input.
• If you comment out the LitteleFS process (open,write,close), the keyboard input does not stuck.
• The version of aruduino-pico is 3.1.0.
• The callstack when stuck varies for core0, but is always the same for core1. (see attached image)

Is there a problem with my usage?
Are there any restrictions or precautions I need to take when using LitteleFS?

[MC-YasuhiroHirano]

This behavior is described in the issue because I think it is a defect.