SdFat SDIO and FreeRTOS

[jeenode]

I am trying to use SdFat to write to SD in a separate task in FreeRTOS and end up with messed up filesystem on SD.
When running a simple (not FReeRTOS) sketch on same board/SD wiring using SdFat and SDIO it works ok.
Any pointers as to what can or cannot be done to get SDIO work in FreeRTOS?
Other tasks in FreeRTOS:

• reading sensors over I2C
• using SX1276 radio via radiolib (uses SPI). I am using async(interrupt driven) send/receive. ISR itself is basically just doing vTaskNotifyGiveFromISR to wake one of tasks- one that read incoming packets and second that finishes/cleans up after transmit. So ISR should be quick.

[earlephilhower]

SDIO is very timing critical compared to plain 1-bit SD card interfacing. Assuming you've covered the basic things like making sure no shared resources and only accessing the libraries from a single thread, maybe something like vTaskPreemptionDisable and/or vTaskSuspendAll when doing any SDIO operations might be needed. If you're in the middle of an SDIO transaction and the task gets swapped out it'll ruin any expected timings...