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-rw-r--r--mm/kmemleak.c43
1 files changed, 40 insertions, 3 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 7cfb7d014a2..466d3900726 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -106,6 +106,7 @@
#define MSECS_MIN_AGE 5000 /* minimum object age for reporting */
#define SECS_FIRST_SCAN 60 /* delay before the first scan */
#define SECS_SCAN_WAIT 600 /* subsequent auto scanning delay */
+#define GRAY_LIST_PASSES 25 /* maximum number of gray list scans */
#define BYTES_PER_POINTER sizeof(void *)
@@ -157,6 +158,8 @@ struct kmemleak_object {
#define OBJECT_REPORTED (1 << 1)
/* flag set to not scan the object */
#define OBJECT_NO_SCAN (1 << 2)
+/* flag set on newly allocated objects */
+#define OBJECT_NEW (1 << 3)
/* the list of all allocated objects */
static LIST_HEAD(object_list);
@@ -270,6 +273,11 @@ static int color_gray(const struct kmemleak_object *object)
return object->min_count != -1 && object->count >= object->min_count;
}
+static int color_black(const struct kmemleak_object *object)
+{
+ return object->min_count == -1;
+}
+
/*
* Objects are considered unreferenced only if their color is white, they have
* not be deleted and have a minimum age to avoid false positives caused by
@@ -447,7 +455,7 @@ static void create_object(unsigned long ptr, size_t size, int min_count,
INIT_HLIST_HEAD(&object->area_list);
spin_lock_init(&object->lock);
atomic_set(&object->use_count, 1);
- object->flags = OBJECT_ALLOCATED;
+ object->flags = OBJECT_ALLOCATED | OBJECT_NEW;
object->pointer = ptr;
object->size = size;
object->min_count = min_count;
@@ -901,6 +909,7 @@ static void kmemleak_scan(void)
struct task_struct *task;
int i;
int new_leaks = 0;
+ int gray_list_pass = 0;
jiffies_last_scan = jiffies;
@@ -921,6 +930,7 @@ static void kmemleak_scan(void)
#endif
/* reset the reference count (whiten the object) */
object->count = 0;
+ object->flags &= ~OBJECT_NEW;
if (color_gray(object) && get_object(object))
list_add_tail(&object->gray_list, &gray_list);
@@ -983,6 +993,7 @@ static void kmemleak_scan(void)
* kmemleak objects cannot be freed from outside the loop because their
* use_count was increased.
*/
+repeat:
object = list_entry(gray_list.next, typeof(*object), gray_list);
while (&object->gray_list != &gray_list) {
cond_resched();
@@ -1000,12 +1011,38 @@ static void kmemleak_scan(void)
object = tmp;
}
+
+ if (scan_should_stop() || ++gray_list_pass >= GRAY_LIST_PASSES)
+ goto scan_end;
+
+ /*
+ * Check for new objects allocated during this scanning and add them
+ * to the gray list.
+ */
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list) {
+ spin_lock_irqsave(&object->lock, flags);
+ if ((object->flags & OBJECT_NEW) && !color_black(object) &&
+ get_object(object)) {
+ object->flags &= ~OBJECT_NEW;
+ list_add_tail(&object->gray_list, &gray_list);
+ }
+ spin_unlock_irqrestore(&object->lock, flags);
+ }
+ rcu_read_unlock();
+
+ if (!list_empty(&gray_list))
+ goto repeat;
+
+scan_end:
WARN_ON(!list_empty(&gray_list));
/*
- * If scanning was stopped do not report any new unreferenced objects.
+ * If scanning was stopped or new objects were being allocated at a
+ * higher rate than gray list scanning, do not report any new
+ * unreferenced objects.
*/
- if (scan_should_stop())
+ if (scan_should_stop() || gray_list_pass >= GRAY_LIST_PASSES)
return;
/*