Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE
[linux-2.6.git] / kernel / exit.c
index ca6a11b..64a5263 100644 (file)
@@ -858,6 +858,34 @@ static void exit_notify(struct task_struct *tsk)
                release_task(tsk);
 }
 
+#ifdef CONFIG_DEBUG_STACK_USAGE
+static void check_stack_usage(void)
+{
+       static DEFINE_SPINLOCK(low_water_lock);
+       static int lowest_to_date = THREAD_SIZE;
+       unsigned long *n = end_of_stack(current);
+       unsigned long free;
+
+       while (*n == 0)
+               n++;
+       free = (unsigned long)n - (unsigned long)end_of_stack(current);
+
+       if (free >= lowest_to_date)
+               return;
+
+       spin_lock(&low_water_lock);
+       if (free < lowest_to_date) {
+               printk(KERN_WARNING "%s used greatest stack depth: %lu bytes "
+                               "left\n",
+                               current->comm, free);
+               lowest_to_date = free;
+       }
+       spin_unlock(&low_water_lock);
+}
+#else
+static inline void check_stack_usage(void) {}
+#endif
+
 fastcall NORET_TYPE void do_exit(long code)
 {
        struct task_struct *tsk = current;
@@ -949,6 +977,7 @@ fastcall NORET_TYPE void do_exit(long code)
        exit_sem(tsk);
        __exit_files(tsk);
        __exit_fs(tsk);
+       check_stack_usage();
        exit_thread();
        cpuset_exit(tsk);
        exit_keys(tsk);