kmemleak: Allow rescheduling during an object scanning
If the object size is bigger than a predefined value (4K in this case),
release the object lock during scanning and call cond_resched().
Re-acquire the lock after rescheduling and test whether the object is
still valid.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 4872673..6debe0d 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -107,6 +107,7 @@
#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 MAX_SCAN_SIZE 4096 /* maximum size of a scanned block */
#define BYTES_PER_POINTER sizeof(void *)
@@ -642,6 +643,7 @@
spin_lock_irqsave(&object->lock, flags);
object->min_count = -1;
+ object->flags |= OBJECT_NO_SCAN;
spin_unlock_irqrestore(&object->lock, flags);
put_object(object);
}
@@ -949,10 +951,21 @@
if (!(object->flags & OBJECT_ALLOCATED))
/* already freed object */
goto out;
- if (hlist_empty(&object->area_list))
- scan_block((void *)object->pointer,
- (void *)(object->pointer + object->size), object, 0);
- else
+ if (hlist_empty(&object->area_list)) {
+ void *start = (void *)object->pointer;
+ void *end = (void *)(object->pointer + object->size);
+
+ while (start < end && (object->flags & OBJECT_ALLOCATED) &&
+ !(object->flags & OBJECT_NO_SCAN)) {
+ scan_block(start, min(start + MAX_SCAN_SIZE, end),
+ object, 0);
+ start += MAX_SCAN_SIZE;
+
+ spin_unlock_irqrestore(&object->lock, flags);
+ cond_resched();
+ spin_lock_irqsave(&object->lock, flags);
+ }
+ } else
hlist_for_each_entry(area, elem, &object->area_list, node)
scan_block((void *)(object->pointer + area->offset),
(void *)(object->pointer + area->offset