I'm not sure this is the right thing to do. Once mp_deinit() is called, no more MicroPython API functions should be called (eg because the GIL is released).

Can you provide a minimal example of the problem you are trying to solve?

Can you provide a minimal example of the problem you are trying to solve?

Deinit a USER_C_MODULE, in this case lvgl on soft-reset, @andrewleech explains this with much more detail in #16063 (comment)

So I've found MICROPY_PORT_DEINIT_FUNC could be used as a simple alternative for this, however
I probably need to investigate it further since stm32 port seems to work fine without this change, but the esp32 port raises a core panic and backtrace points to mp_deinit.

What happens is that lvgl uses micropython garbage collector to allocate/free memory, so at soft-reset gc_sweep_all() frees everything and then lvgl.deinit() at mp_deinit will try to free already freed memory which in esp32 case raises a core panic.

Note that moving gc_sweep_all and esp_native_code_free_all after mp_deinit works too.

Once mp_deinit() is called, no more MicroPython API functions should be called

This includes the garbage collector I guess?

This includes the garbage collector I guess?

Correct. It can't run because the GIL is released.

What happens is that lvgl uses micropython garbage collector to allocate/free memory, so at soft-reset gc_sweep_all() frees everything and then lvgl.deinit() at mp_deinit will try to free already freed memory which in esp32 case raises a core panic.

It sounds like lvgl should be changed so that it doesn't free memory in its deinit function. It should rely on gc_sweep_all() to do that for it.

lvgl can also use finalisers, which will always be run as part of gc_sweep_all() if there are any objects remaining at soft reset time.

It sounds like lvgl should be changed so that it doesn't free memory in its deinit function. It should rely on gc_sweep_all() to do that for it.

Ah that was it, I've only needed to reset lvgl root pointers, gc_sweep_all() handles the rest, @dpgeorge thanks for the support 🙏🏼