driver: spi: spi_release() implementations requires an owner check

Without this check, `spi_context_unlock_unconditionally()` is capable
to release the SPI bus semaphore (ctx->lock) which might be taken by
another SPI slave device in the meantime.

Actually, this race condition happens when `spi_release()` is called
when the SPI slave device in question (spi_cfg) has already released
its chip select and also the SPI bus lock semaphore.

So, any not required call of `spi_release()` may result in a SPI
communication issue where the SPI bus lock, held by another SPI
slave device, is prematurely released.
The observable result is the simultaneous engagement of two SPI
chip selects after such an SPI release call.

Signed-off-by: Stefan Schwendeler <[email protected]>

Author: GardeningStevie

drivers/spi/spi_nrfx_spim.c

@@ -733,6 +733,12 @@ static int spi_nrfx_release(const struct device *dev,
 {
 	struct spi_nrfx_data *dev_data = dev->data;
 
+#ifdef CONFIG_MULTITHREADING
+	if (dev_data->ctx.owner != spi_cfg) {
+		return -EALREADY;
+	}
+#endif
+
 	if (!spi_context_configured(&dev_data->ctx, spi_cfg)) {
 		return -EINVAL;
 	}