BT_DRV_RX_STACK_SIZE is too small and can't be configured. It needs to be more than 512 bytes in released versions of Zephyr, or 640 bytes, on the main branch. Note: I'm using the nRF SDK v2.5.2, which is not the latest, but the driver hasn't changed in any meaningful way since.
zephyr,bt-hci-spi on a nRF9160 to a zephyr,bt-hci-spi-slave on a nRF52810. bt_spi_rx_thread() in spi.c causes segfault on the host (nRF9160) because of stack overflow. I can nail it down to the call to bt_spi_transcieve().
Increasing the value in Kconfig to 1024 seems to work. The rest of my configuration is irrelevant since this is isolated to a specific thread and its task size.
(previously posted to https://github.com/zephyrproject-rtos/zephyr/issues/80109 who refers to Nordic Semi)
