How do I stop wifi so that it can be successfully restarted? [SOLVED]

[adamwilt]

I'm trying to build wifi AP and STA modes that I can start and stop at will.

I call esp_netif_init() once, at startup.

Then I start up wifi using code similar to this simplified pseudocode:

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    _espNetif = esp_netif_create_default_wifi_[ap|station]();
    esp_wifi_init();
    esp_wifi_set_mode();
    esp_wifi_set_config();
    esp_wifi_start();

And to stop wifi, I do this:

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    esp_wifi_stop();
    esp_wifi_deinit();
    esp_netif_destroy(_espNetif);

It works great the first time, but subsequent starts fail as soon as any wifi traffic occurs. In the code as shown, it's a crash:

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Guru Meditation Error: Core  0 panic'ed (InstructionFetchError). Exception was unhandled.

If I reduce the amount of teardown/rebuild — for example, if I just call esp_wifi_stop() to stop wifi and call esp_wifi_start() to restart it — the code won't crash, but it will hang as soon as wifi traffic happens, and in hangs in the same place (as far as I can tell) that it crashes in the full teardown/rebuild code.

So what am I missing?

Solution: Add a call to esp_wifi_clear_default_wifi_driver_and_handlers() in the teardown sequence, e.g.,

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    esp_wifi_stop();
    esp_wifi_deinit();
    esp_wifi_clear_default_wifi_driver_and_handlers(_espNetif); // <-add this!
    esp_netif_destroy(_espNetif);

(Post left in place in case it's helpful to anyone else.)