Avoid deadlock by disabling interrupts in print! and serial_print! macros

src/serial.rs

@@ -13,10 +13,14 @@ lazy_static! {
 #[doc(hidden)]
 pub fn _print(args: ::core::fmt::Arguments) {
     use core::fmt::Write;
+    use x86_64::instructions::interrupts;
+
+    interrupts::without_interrupts(|| {
         SERIAL1
             .lock()
             .write_fmt(args)
             .expect("Printing to serial failed");
+    });
 }
 
 /// Prints to the host through the serial interface.

src/vga_buffer.rs

@@ -135,10 +135,16 @@ macro_rules! println {
     ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
 }
 
+/// Prints the given formatted string to the VGA text buffer
+/// through the global `WRITER` instance.
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
+    use x86_64::instructions::interrupts;
+
+    interrupts::without_interrupts(|| {
         WRITER.lock().write_fmt(args).unwrap();
+    });
 }
 
 #[cfg(test)]