[PATCH 4.19 020/105] Drivers: hv: vmbus: fix double free in the error path of vmbus_add_channel_work()

Greg Kroah-Hartman
2022-12-05T19:18:36Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit f92a4b50f0bd7fd52391dc4bb9a309085d278f91 ]

In the error path of vmbus_device_register(), device_unregister()
is called, which calls vmbus_device_release(). The latter frees
the struct hv_device that was passed in to vmbus_device_register().
So remove the kfree() in vmbus_add_channel_work() to avoid a double
free.

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Suggested-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20221119081135.1564691-2-yangyingliang@huawei.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hv/channel_mgmt.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index a3f6933f94e3..ccfa5ceb43c0 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -508,13 +508,17 @@ static void vmbus_add_channel_work(struct work_struct *work)
* Add the new device to the bus. This will kick off device-driver
* binding which eventually invokes the device driver's AddDevice()
* method.
+ *
+ * If vmbus_device_register() fails, the 'device_obj' is freed in
+ * vmbus_device_release() as called by device_unregister() in the
+ * error path of vmbus_device_register(). In the outside error
+ * path, there's no need to free it.
*/
ret = vmbus_device_register(newchannel->device_obj);

if (ret != 0) {
pr_err("unable to add child device object (relid %d)\n",
newchannel->offermsg.child_relid);
- kfree(newchannel->device_obj);
goto err_deq_chan;
}

--
2.35.1