From: Ben Pfaff <blp@cs.stanford.edu>
Date: Wed, 20 Jul 2005 04:44:55 +0000 (+0000)
Subject: Eliminate race condition in console_print_stats() found by Sorav's
X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?p=pintos-anon;a=commitdiff_plain;h=076c62799001f43a6f216755e71578d7143e1e05

Eliminate race condition in console_print_stats() found by Sorav's
Checkbochs tool.
---

diff --git a/src/lib/kernel/console.c b/src/lib/kernel/console.c
index 53e08a0..176dd06 100644
--- a/src/lib/kernel/console.c
+++ b/src/lib/kernel/console.c
@@ -52,13 +52,6 @@ console_init (void)
   lock_init (&console_lock);
 }
 
-/* Prints console statistics. */
-void
-console_print_stats (void) 
-{
-  printf ("Console: %lld characters output\n", write_cnt);
-}
-
 /* Acquires the console lock. */
 static void
 acquire_console (void) 
@@ -93,6 +86,15 @@ console_locked_by_current_thread (void)
   return intr_context () || lock_held_by_current_thread (&console_lock);
 }
 
+/* Prints console statistics. */
+void
+console_print_stats (void) 
+{
+  acquire_console ();
+  printf ("Console: %lld characters output\n", write_cnt);
+  release_console ();
+}
+
 /* The standard vprintf() function,
    which is like printf() but uses a va_list.
    Writes its output to both vga display and serial port. */