Merge branch 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebieder...

[linux-2.6-microblaze.git] / drivers / misc / lkdtm / bugs.c

diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c
index 86556ad..d9fcfd3 100644 (file)
--- a/drivers/misc/lkdtm/bugs.c
+++ b/drivers/misc/lkdtm/bugs.c
@@ -32,12 +32,20 @@ static int recur_count = REC_NUM_DEFAULT;
 
 static DEFINE_SPINLOCK(lock_me_up);
 
-static int recursive_loop(int remaining)
+/*
+ * Make sure compiler does not optimize this function or stack frame away:
+ * - function marked noinline
+ * - stack variables are marked volatile
+ * - stack variables are written (memset()) and read (pr_info())
+ * - function has external effects (pr_info())
+ * */
+static int noinline recursive_loop(int remaining)
 {
-       char buf[REC_STACK_SIZE];
+       volatile char buf[REC_STACK_SIZE];
 
-       /* Make sure compiler does not optimize this away. */
-       memset(buf, (remaining & 0xff) | 0x1, REC_STACK_SIZE);
+       memset((void *)buf, remaining & 0xFF, sizeof(buf));
+       pr_info("loop %d/%d ...\n", (int)buf[remaining % sizeof(buf)],
+               recur_count);
        if (!remaining)
                return 0;
        else
@@ -81,9 +89,12 @@ void lkdtm_LOOP(void)
                ;
 }
 
-void lkdtm_OVERFLOW(void)
+void lkdtm_EXHAUST_STACK(void)
 {
-       (void) recursive_loop(recur_count);
+       pr_info("Calling function with %d frame size to depth %d ...\n",
+               REC_STACK_SIZE, recur_count);
+       recursive_loop(recur_count);
+       pr_info("FAIL: survived without exhausting stack?!\n");
 }
 
 static noinline void __lkdtm_CORRUPT_STACK(void *stack)