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Commit af98603d authored by Catalin Marinas's avatar Catalin Marinas
Browse files

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: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 1e23502c

mm/kmemleak.c

+17 −4
Original line number Diff line number Diff line
@@ -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 @@ static void make_black_object(unsigned long ptr) 


	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 @@ static void scan_object(struct kmemleak_object *object) 
	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