media: software_node: Fix refcounts in software_node_get_next_child()

stable inclusion
from stable-5.10.20
commit f7765a1143c3f3b617c693d1ae6d9db356d7b020
bugzilla: 50608

--------------------------------

[ Upstream commit fb5ec981 ]

The software_node_get_next_child() function currently does not hold
references to the child software_node that it finds or put the ref that
is held against the old child - fix that.

Fixes: 59abd836 ("drivers: base: Introducing software nodes to the firmware node framework")
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Scally <djrscally@gmail.com>
Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/base/swnode.c

@@ -443,14 +443,18 @@ software_node_get_next_child(const struct fwnode_handle *fwnode,
 	struct swnode *c = to_swnode(child);
 
 	if (!p || list_empty(&p->children) ||
-	    (c && list_is_last(&c->entry, &p->children)))
+	    (c && list_is_last(&c->entry, &p->children))) {
+		fwnode_handle_put(child);
 		return NULL;
+	}
 
 	if (c)
 		c = list_next_entry(c, entry);
 	else
 		c = list_first_entry(&p->children, struct swnode, entry);
-	return &c->fwnode;
+
+	fwnode_handle_put(child);
+	return fwnode_handle_get(&c->fwnode);
 }
 
 static struct fwnode_handle *