esp32/mpthreadport: Fix double delete of tasks on soft reset.

Python threads (created via the `_thread` module) are backed by a FreeRTOS
task.  Managing the deletion of the task can be tricky, and there are
currently some bugs with this in the esp32 port.

The actual crash seen was in FreeRTOS' `uxListRemove()`, and that's because
of two calls to `vTaskDelete()` for the same task: one in
`freertos_entry()` when the task ran to completion, and the other in
`mp_thread_deinit()`.  The latter tried to delete the task a second time
because it was still in the linked list, because `vTaskPreDeletionHook()`
had not yet been called.  And the reason `vTaskPreDeletionHook()` was yet
to be called is because the FreeRTOS idle task was starved.

This commit fixes that.

There are three things done by this commit:
- remove the `vTaskPreDeletionHook`, it's not needed anymore because task
  stack memory is allocated by the IDF, not on the MicroPython heap
- when a task finishes it now removes itself from the linked list, just
  before it deletes itself
- on soft reset, all tasks are deleted and removed from the linked list in
  one swoop (while the mutex is held)

Signed-off-by: Damien George <damien@micropython.org>

0 files changed, 0 insertions, 0 deletions