1 files changed, 73 insertions, 14 deletions

diff --git a/drivers/misc/lkdtm_bugs.c b/drivers/misc/lkdtm_bugs.c
index 91edd0b55e5c..cba0837aee2e 100644
--- a/drivers/misc/lkdtm_bugs.c
+++ b/drivers/misc/lkdtm_bugs.c
@@ -6,6 +6,7 @@
  */
 #include "lkdtm.h"
 #include <linux/list.h>
+#include <linux/refcount.h>
 #include <linux/sched.h>
 
 struct lkdtm_list {
@@ -129,28 +130,86 @@ void lkdtm_HUNG_TASK(void)
 	schedule();
 }
 
-void lkdtm_ATOMIC_UNDERFLOW(void)
+void lkdtm_REFCOUNT_SATURATE_INC(void)
 {
-	atomic_t under = ATOMIC_INIT(INT_MIN);
+	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);
 
-	pr_info("attempting good atomic increment\n");
-	atomic_inc(&under);
-	atomic_dec(&under);
+	pr_info("attempting good refcount decrement\n");
+	refcount_dec(&over);
+	refcount_inc(&over);
 
-	pr_info("attempting bad atomic underflow\n");
-	atomic_dec(&under);
+	pr_info("attempting bad refcount inc overflow\n");
+	refcount_inc(&over);
+	refcount_inc(&over);
+	if (refcount_read(&over) == UINT_MAX)
+		pr_err("Correctly stayed saturated, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount wrapped\n");
+}
+
+void lkdtm_REFCOUNT_SATURATE_ADD(void)
+{
+	refcount_t over = REFCOUNT_INIT(UINT_MAX - 1);
+
+	pr_info("attempting good refcount decrement\n");
+	refcount_dec(&over);
+	refcount_inc(&over);
+
+	pr_info("attempting bad refcount add overflow\n");
+	refcount_add(2, &over);
+	if (refcount_read(&over) == UINT_MAX)
+		pr_err("Correctly stayed saturated, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount wrapped\n");
+}
+
+void lkdtm_REFCOUNT_ZERO_DEC(void)
+{
+	refcount_t zero = REFCOUNT_INIT(1);
+
+	pr_info("attempting bad refcount decrement to zero\n");
+	refcount_dec(&zero);
+	if (refcount_read(&zero) == 0)
+		pr_err("Stayed at zero, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount went crazy\n");
 }
 
-void lkdtm_ATOMIC_OVERFLOW(void)
+void lkdtm_REFCOUNT_ZERO_SUB(void)
 {
-	atomic_t over = ATOMIC_INIT(INT_MAX);
+	refcount_t zero = REFCOUNT_INIT(1);
+
+	pr_info("attempting bad refcount subtract past zero\n");
+	if (!refcount_sub_and_test(2, &zero))
+		pr_info("wrap attempt was noticed\n");
+	if (refcount_read(&zero) == 1)
+		pr_err("Correctly stayed above 0, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount wrapped\n");
+}
 
-	pr_info("attempting good atomic decrement\n");
-	atomic_dec(&over);
-	atomic_inc(&over);
+void lkdtm_REFCOUNT_ZERO_INC(void)
+{
+	refcount_t zero = REFCOUNT_INIT(0);
 
-	pr_info("attempting bad atomic overflow\n");
-	atomic_inc(&over);
+	pr_info("attempting bad refcount increment from zero\n");
+	refcount_inc(&zero);
+	if (refcount_read(&zero) == 0)
+		pr_err("Stayed at zero, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount went past zero\n");
+}
+
+void lkdtm_REFCOUNT_ZERO_ADD(void)
+{
+	refcount_t zero = REFCOUNT_INIT(0);
+
+	pr_info("attempting bad refcount addition from zero\n");
+	refcount_add(2, &zero);
+	if (refcount_read(&zero) == 0)
+		pr_err("Stayed at zero, but no BUG?!\n");
+	else
+		pr_err("Fail: refcount went past zero\n");
 }
 
 void lkdtm_CORRUPT_LIST_ADD(void)