Summary

When using firmware built from the master branch calling _thread.start_new_thread freezes the whole machine. v1.22.0-preview and earlier works as expected.

Using Raspberry Pi Pico W.

I went back to find the commit where it breaks, and i found the breaking point: bcbdee2

• 2d363a2 still works
• bcbdee2 does not work anymore

Scenario

Im using a Raspberry Pi Pico W with firmware built from the repository (make etc.) In my application, right at the start of boot.py I started a process on the second thread that constantly measured the orientation, then continued as normal, but yesterday the whole program started freezing.

After some testing I found out that calling _thread.start_new_thread(test_function, ()) freezes the machine, it cannot be stopped with ctrl-c or any other method.

I tested with this file, then importing and running test()

import _thread

def test1():
    for i in  range(4):
        print(f"test1-{i}")

def test2():
    for i in  range(4):
        print(f"test2-{i}")

def test():
    print("Main thread:")
    test1()

    print("In second thread:")
    _thread.start_new_thread(test2, ())
    print("Main thread again:")
    test1()

With 2d363a2 and earlier I get the expected:

Main thread:
test1-0
test1-1
test1-2
test1-3
In second thread:
Main thread again:
test2-0
test1-0
test2-1
test1-1
test2-2
test1-2
test2-3
test1-3

But after bcbdee2 I get:

then freezes completely. Power cycling does make the device responsive again.

Sorry about the format, first time creating an issue.