drivers: serial: esp32_usb: fix interrupt-enable race condition

After enabling interrupts, serial_esp32_usb_irq_tx_enable() calls the
interrupt handler to handle any old events that occurred while interrupts
were disabled.  However, this happens in the callers context, so if an
interrupt arrives during the call, it will call the interrupt handler again
resulting in corruption if the interrupt handler is not reentrant.

Fixes #74569

Signed-off-by: Eric Holmberg <[email protected]>

Author: EricNRS

drivers/serial/serial_esp32_usb.c

@@ -142,7 +142,9 @@ static void serial_esp32_usb_irq_tx_enable(const struct device *dev)
 	usb_serial_jtag_ll_ena_intr_mask(USB_SERIAL_JTAG_INTR_SERIAL_IN_EMPTY);
 
 	if (data->irq_cb != NULL) {
+		unsigned int key = irq_lock();
 		data->irq_cb(dev, data->irq_cb_data);
+		arch_irq_unlock(key);
 	}
 }
 
@@ -220,8 +222,8 @@ static void serial_esp32_usb_irq_callback_set(const struct device *dev,
 {
 	struct serial_esp32_usb_data *data = dev->data;
 
-	data->irq_cb = cb;
 	data->irq_cb_data = cb_data;
+	data->irq_cb = cb;
 }
 
 static void serial_esp32_usb_isr(void *arg)