diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 565b8dac5782..5a4ff505fd12 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -552,6 +552,7 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head)
 {
 	struct request_queue *q = container_of(rcu_head, struct request_queue,
 					       rcu_head);
+	printk("freeing q\n");
 	kmem_cache_free(blk_requestq_cachep, q);
 }
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index bb0dfb1c7af1..6475dac5f3bc 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1496,6 +1496,8 @@ static int blkdev_open(struct inode * inode, struct file * filp)
 	return blkdev_get(bdev, filp->f_mode, filp);
 }
 
+#include <linux/delay.h>
+
 static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 {
 	struct gendisk *disk = bdev->bd_disk;
@@ -1531,6 +1533,12 @@ static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
 
 		put_disk(disk);
 		module_put(owner);
+
+		if (!strcmp(current->comm, "systemd-udevd")) {
+			printk("sleep start %d\n", task_pid_nr(current));
+			ssleep(3);
+			printk("sleep end %d\n", task_pid_nr(current));
+		}
 	}
 	mutex_unlock(&bdev->bd_mutex);
 	bdput(bdev);
diff --git a/fs/inode.c b/fs/inode.c
index 1be5f9003eb3..10625eeb7816 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1490,6 +1490,8 @@ void iput(struct inode *inode)
 {
 	if (!inode)
 		return;
+	if (inode->i_wb)
+		BUG_ON(atomic_long_read(&inode->i_wb->refcnt.count) == 0x6b6b6b6b6b6b6b6b);
 	BUG_ON(inode->i_state & I_CLEAR);
 retry:
 	if (atomic_dec_and_lock(&inode->i_count, &inode->i_lock)) {