2 files changed, 14 insertions, 0 deletions

diff --git a/include/linux/magic.h b/include/linux/magic.h
index 1fa0c2ce4dec..74e68e201166 100644
--- a/include/linux/magic.h
+++ b/include/linux/magic.h
@@ -42,4 +42,5 @@
 #define FUTEXFS_SUPER_MAGIC     0xBAD1DEA
 #define INOTIFYFS_SUPER_MAGIC   0x2BAD1DEA
 
+#define STACK_END_MAGIC         0x57AC6E9D
 #endif /* __LINUX_MAGIC_H__ */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d6a515158783..c5181e77f305 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1969,6 +1969,19 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
 
 extern void thread_info_cache_init(void);
 
+#ifdef CONFIG_DEBUG_STACK_USAGE
+static inline unsigned long stack_not_used(struct task_struct *p)
+{
+        unsigned long *n = end_of_stack(p);
+
+        do {    /* Skip over canary */
+                n++;
+        } while (!*n);
+
+        return (unsigned long)n - (unsigned long)end_of_stack(p);
+}
+#endif
+
 /* set thread flags in other task's structures
  * - see asm/thread_info.h for TIF_xxxx flags available
  */