kernel: print log messages directly to the console if log_buffer is full

kernel/printk.c

@@ -63,6 +63,10 @@ int printk(const char *format, ...)
 	msg[len] = '\n';
 	msg[len + 1] = '\0';
 
+	if (log_buffer_writep == LOG_BUFFER_SIZE - 1) {
+		console_write(early_console, msg, len + 1);
+	}
+
 	unsigned long flags;
 	spin_lock_irqsave(&log_buffer_lock, &flags);
 	save_log_message(msg);