iommu: Fix reference count leak in iommu_group_alloc.

[ Upstream commit 7cc31613734c4870ae32f5265d576ef296621343 ]

kobject_init_and_add() takes reference even when it fails.
Thus, when kobject_init_and_add() returns an error,
kobject_put() must be called to properly clean up the kobject.

Fixes: d72e31c93746 ("iommu: IOMMU Groups")
Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Link: https://lore.kernel.org/r/20200527210020.6522-1-wu000273@umn.edu
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 00e1c90..85ef6c9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -392,7 +392,7 @@
 				   NULL, "%d", group->id);
 	if (ret) {
 		ida_simple_remove(&iommu_group_ida, group->id);
-		kfree(group);
+		kobject_put(&group->kobj);
 		return ERR_PTR(ret);
 	}