diff --git a/tlsf.c b/tlsf.c
index 68105d0..a8018c7 100644
--- a/tlsf.c
+++ b/tlsf.c
@@ -668,14 +668,32 @@ static void integrity_walker(void* ptr, size_t size, int used, void* user)
 	const size_t this_block_size = block_size(block);
 
 	int status = 0;
-	(void)used;
 	tlsf_insist(integ->prev_status == this_prev_status && "prev status incorrect");
 	tlsf_insist(size == this_block_size && "block size incorrect");
 
+	if (tlsf_check_hook != NULL)
+	{
+		/* block_size(block) returns the size of the usable memory when the block is allocated.
+		 * As the block under test is free, we need to subtract to the block size the next_free
+		 * and prev_free fields of the block header as they are not a part of the usable memory
+		 * when the block is free. In addition, we also need to subtract the size of prev_phys_block
+		 * as this field is in fact part of the current free block and not part of the next (allocated)
+		 * block. Check the comments in block_split function for more details.
+		 */
+		const size_t actual_free_block_size = used ? this_block_size : 
+													 this_block_size - offsetof(block_header_t, next_free)- block_header_overhead;
+		
+		void* ptr_block = used ? (void*)block + block_start_offset :
+								 (void*)block + sizeof(block_header_t);
+
+		tlsf_insist(tlsf_check_hook(ptr_block, actual_free_block_size, !used));
+	}
+
 	integ->prev_status = this_status;
 	integ->status += status;
 }
 
+
 int tlsf_check(tlsf_t tlsf)
 {
 	int i, j;
@@ -722,23 +740,6 @@ int tlsf_check(tlsf_t tlsf)
 				mapping_insert(control, block_size(block), &fli, &sli);
 				tlsf_insist(fli == i && sli == j && "block size indexed in wrong list");
 
-				if (tlsf_check_hook != NULL)
-				{
-					/* block_size(block) returns the size of the usable memory when the block is allocated.
-					 * As the block under test is free, we need to subtract to the block size the next_free
-					 * and prev_free fields of the block header as they are not a part of the usable memory
-					 * when the block is free. In addition, we also need to subtract the size of prev_phys_block
-					 * as this field is in fact part of the current free block and not part of the next (allocated)
-					 * block. Check the comments in block_split function for more details.
-					 */
-					const size_t actual_free_block_size = block_size(block) 
-															- offsetof(block_header_t, next_free)
-															- block_header_overhead;
-
-					tlsf_insist(tlsf_check_hook((void*)block + sizeof(block_header_t),
-												actual_free_block_size, is_block_free));
-				}
-
 				block = block->next_free;
 			}
 		}