don't leak memory if exec() arguments are invalid.

1 files changed, 19 insertions, 1 deletions

diff --git a/user/usertests.c b/user/usertests.c
index d2076c7..af3e5db 100644
--- a/user/usertests.c
+++ b/user/usertests.c
@@ -2016,6 +2016,7 @@ sbrkbugs(char *s)
 // has this bug, it will panic: balloc: out of blocks. 
 // assumed_free may need to be raised to be
 // more than the number of free blocks.
+// this test takes a long time.
 void
 badwrite(char *s)
 {
@@ -2048,6 +2049,22 @@ badwrite(char *s)
   exit(0);
 }
 
+// test whether exec() leaks memory if one of the
+// arguments is invalid. the test passes if
+// the kernel doesn't panic.
+void
+badarg(char *s)
+{
+  for(int i = 0; i < 50000; i++){
+    char *argv[2];
+    argv[0] = (char*)0xffffffff;
+    argv[1] = 0;
+    exec("echo", argv);
+  }
+  
+  exit(0);
+}
+
 // run each test in its own process. run returns 1 if child's exit()
 // indicates success.
 int
@@ -2087,7 +2104,8 @@ main(int argc, char *argv[])
   } tests[] = {
     {pgbug, "pgbug" },
     {sbrkbugs, "sbrkbugs" },
-    {badwrite, "badwrite" },
+    // {badwrite, "badwrite" },
+    {badarg, "badarg" },
     {reparent, "reparent" },
     {twochildren, "twochildren"},
     {forkfork, "forkfork"},