[PATCH] RDMA/nldev: Put the device when dellink fails

[PATCH] RDMA/nldev: Put the device when dellink fails

[lirongqing]

From: Li RongQing <lirongqing@baidu.com>

nldev_dellink() takes a device reference through
ib_device_get_by_index() and normally hands it over to
ib_unregister_device_and_put(). The error path of the ->dellink
callback returns without releasing it, so the reference is leaked.

Once that happens, any later unregistration of the device blocks
forever, because disable_device() drops its own reference and then
waits for the refcount to drain. No in-tree driver returns an error
from ->dellink today, so the leak is currently latent.

Put the device before returning the error.

Fixes: a60e3f3d6fba ("RDMA/nldev: Add dellink function pointer")
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
 drivers/infiniband/core/nldev.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/core/nldev.c b/drivers/infiniband/core/nldev.c
index a4014a2..a1542ed 100644
--- a/drivers/infiniband/core/nldev.c
+++ b/drivers/infiniband/core/nldev.c
@@ -1895,8 +1895,10 @@ static int nldev_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
 		mutex_lock(&nldev_dellink_mutex);
 		err = device->link_ops->dellink(device);
 		mutex_unlock(&nldev_dellink_mutex);
-		if (err)
+		if (err) {
+			ib_device_put(device);
 			return err;
+		}
 	}
 
 	ib_unregister_device_and_put(device);
-- 
2.9.4