EDAC/sysfs: Fix memory leak when creating a csrow object

In edac_create_csrow_object(), the reference to the object is not
released when adding the device to the device hierarchy fails
(device_add()). This may result in a memory leak.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: https://lkml.kernel.org/r/1555554438-103953-1-git-send-email-bianpan2016@163.com

drivers/edac/edac_mc_sysfs.c

@@ -404,6 +404,8 @@ static inline int nr_pages_per_csrow(struct csrow_info *csrow)
 static int edac_create_csrow_object(struct mem_ctl_info *mci,
 				    struct csrow_info *csrow, int index)
 {
+	int err;
+
 	csrow->dev.type = &csrow_attr_type;
 	csrow->dev.groups = csrow_dev_groups;
 	device_initialize(&csrow->dev);
@@ -415,7 +417,11 @@ static int edac_create_csrow_object(struct mem_ctl_info *mci,
 	edac_dbg(0, "creating (virtual) csrow node %s\n",
 		 dev_name(&csrow->dev));
 
-	return device_add(&csrow->dev);
+	err = device_add(&csrow->dev);
+	if (err)
+		put_device(&csrow->dev);
+
+	return err;
 }
 
 /* Create a CSROW object under specifed edac_mc_device */