linux-kernel - [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel

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Date:   Fri,  4 Feb 2022 01:30:08 +0800
From:   Miaoqian Lin <linmq006@...il.com>
To:     juvazq@...ux.microsoft.com
Cc:     decui@...rosoft.com, gregkh@...uxfoundation.org,
        haiyangz@...rosoft.com, kys@...rosoft.com, linmq006@...il.com,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        sthemmin@...rosoft.com, wei.liu@...nel.org
Subject: [PATCH v2] Drivers: hv: vmbus: Fix memory leak in vmbus_add_channel_kobj

kobject_init_and_add() takes reference even when it fails.
According to the doc of kobject_init_and_add()：

   If this function returns an error, kobject_put() must be called to
   properly clean up the memory associated with the object.

Fix memory leak by calling kobject_put().

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Signed-off-by: Miaoqian Lin <linmq006@...il.com>
---
Changes in v2:
- Add cleanup when sysfs_create_group() fails

kobject_uevent() is used for notifying userspace by sending an uevent,
I don't think we need to do error handling for it.
---
 drivers/hv/vmbus_drv.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 17bf55fe3169..34a4fd21bdf5 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2028,8 +2028,10 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
 	kobj->kset = dev->channels_kset;
 	ret = kobject_init_and_add(kobj, &vmbus_chan_ktype, NULL,
 				   "%u", relid);
-	if (ret)
+	if (ret) {
+		kobject_put(kobj);
 		return ret;
+	}
 
 	ret = sysfs_create_group(kobj, &vmbus_chan_group);
 
@@ -2038,6 +2040,7 @@ int vmbus_add_channel_kobj(struct hv_device *dev, struct vmbus_channel *channel)
 		 * The calling functions' error handling paths will cleanup the
 		 * empty channel directory.
 		 */
+		kobject_put(kobj);
 		dev_err(device, "Unable to set up channel sysfs files\n");
 		return ret;
 	}
-- 
2.25.1