Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE
Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE.
This also adds UML support.
Tested on UML and i386.
[akpm@linux-foundation.org: cleanups, speedups, tweaks]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/exit.c b/kernel/exit.c
index ca6a11b..64a5263 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -858,6 +858,34 @@
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 @@
exit_sem(tsk);
__exit_files(tsk);
__exit_fs(tsk);
+ check_stack_usage();
exit_thread();
cpuset_exit(tsk);
exit_keys(tsk);