linux-kernel - [PATCH] vfio/mdev: Fix reference count leak in add_mdev_supported

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Date:   Wed, 27 May 2020 21:01:09 -0500
From:   wu000273@....edu
To:     kjlu@....edu
Cc:     wu000273@....edu, Kirti Wankhede <kwankhede@...dia.com>,
        Alex Williamson <alex.williamson@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>, Neo Jia <cjia@...dia.com>,
        Dong Jia Shi <bjsdjshi@...ux.vnet.ibm.com>,
        Jike Song <jike.song@...el.com>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] vfio/mdev: Fix reference count leak in add_mdev_supported_type.

From: Qiushi Wu <wu000273@....edu>

kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object. Thus,
replace kfree() by kobject_put() to fix this issue. Previous
commit "b8eb718348b8" fixed a similar problem.

Fixes: 7b96953bc640 ("vfio: Mediated device Core driver")
Signed-off-by: Qiushi Wu <wu000273@....edu>
---
 drivers/vfio/mdev/mdev_sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vfio/mdev/mdev_sysfs.c b/drivers/vfio/mdev/mdev_sysfs.c
index 8ad14e5c02bf..917fd84c1c6f 100644
--- a/drivers/vfio/mdev/mdev_sysfs.c
+++ b/drivers/vfio/mdev/mdev_sysfs.c
@@ -110,7 +110,7 @@ static struct mdev_type *add_mdev_supported_type(struct mdev_parent *parent,
 				   "%s-%s", dev_driver_string(parent->dev),
 				   group->name);
 	if (ret) {
-		kfree(type);
+		kobject_put(&type->kobj);
 		return ERR_PTR(ret);
 	}
 
-- 
2.17.1