DMA capable memory decreasing over time

[finger563]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

What is the expected behavior?

We do not leak memory and do not run out of DMA-capable memory (needed for LCD SPI).

What is the actual behavior?

Running Nofrendo (NES) emluation seems to decrease DMA-capable memory:

Steps to reproduce.

1. Run GBC rom
2. Run NES rom
3. Run another NES rom
4. Run GBC rom
5. Run another GBC rom

See that DMA decreases between steps 1->2 and steps 2->3, but not 3->4 or 4->5.

Build or installation Logs.

No response

More Information.

This may be related to nofrendo itself (and the modiciations I've made to it), or it could be more general and associated with one of the following:

1. How the screen is communicated with (e.g. emulators use DMA capable memory, but the menu/gui and clearing commands use non-dma capable memory)
2. Somewhere in the emulator(s) which is using stack that's not clearing for some reason
3. Somewhere in the emulator(s) which are using mallocs but not freeing the memory
4. Perhaps the internal allocation of dma-capable memory in the spi transaction in ESP-IDF is leaking memory during the cases when non-dma capable memory is being passed in?

I don't have hard data for it yet, but I believe the memory leak is worse when the steps include loading save states in the emulators.
6. Something else entirely?

[finger563]

I've added some logging to spi_master.c and seen that there are cases where it is attempting to free memory that was not allocated. This happens during a timeout when trying to get the trans_result. Possibly related ESP-IDF issue here: espressif/esp-idf#10066