1 files changed, 32 insertions, 0 deletions
diff --git a/src/examples/create-bad.c b/src/examples/create-bad.c
new file mode 100644
index 0000000..4a9688a
--- /dev/null
+++ b/src/examples/create-bad.c
@@ -0,0 +1,32 @@
+/* The following program should be killed by the kernel because the
+   string sent with create starts at one page (the BSS page) and ends
+   outside of it in a page that is not allocated.
+
+   If user memory accesses are not handled correctly by the kernel,
+   then pintos will crash with a page fault exception.
+   
+   Author: Mattias Eriksson
+*/
+
+#include <syscall.h>
+#include <stdio.h>
+#include <string.h>
+
+#define PGS 4096 /* page size */
+#define PMASK 0xfffff000
+
+static char inbss;
+
+int
+main (void)
+{
+  char * bss_page = (char*) ((int)(&inbss) & PMASK);
+  printf("inbss and bss_page: %p, %p\n", &inbss, bss_page);
+  printf("This program should be killed by the kernel.\n");
+
+  memset ( bss_page, 'a', PGS );
+  create (bss_page+PGS-5, 1024);
+  printf("ERROR: this point should not be reached\n");
+  
+  exit(0);
+}