net: appletalk: Fix device refcount leak in atrtr_create()

[ Upstream commit 711c80f7d8b163d3ecd463cd96f07230f488e750 ]

When updating an existing route entry in atrtr_create(), the old device
reference was not being released before assigning the new device,
leading to a device refcount leak. Fix this by calling dev_put() to
release the old device reference before holding the new one.

Fixes: c7f905f ("[ATALK]: Add missing dev_hold() to atrtr_create().")
Signed-off-by: Kito Xu <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Author: veritas501

net/appletalk/ddp.c

@@ -563,6 +563,7 @@ static int atrtr_create(struct rtentry *r, struct net_device *devhint)
 
 	/* Fill in the routing entry */
 	rt->target  = ta->sat_addr;
+	dev_put(rt->dev); /* Release old device */
 	dev_hold(devhint);
 	rt->dev     = devhint;
 	rt->flags   = r->rt_flags;