net: sched: Fix qdisc_rate_table refcount leak when get tcf_block failed

stable inclusion
from stable-5.10.65
commit f96bc82e0348be15def7b98ebfd6e276d2c1e8a1
bugzilla: 182361 https://gitee.com/openeuler/kernel/issues/I4EH3U

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f96bc82e0348be15def7b98ebfd6e276d2c1e8a1

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

[ Upstream commit c6607012 ]

The reference counting issue happens in one exception handling path of
cbq_change_class(). When failing to get tcf_block, the function forgets
to decrease the refcount of "rtab" increased by qdisc_put_rtab(),
causing a refcount leak.

Fix this issue by jumping to "failure" label when get tcf_block failed.

Fixes: 6529eaba ("net: sched: introduce tcf block infractructure")
Signed-off-by: NXiyu Yang <xiyuyang19@fudan.edu.cn>
Reviewed-by: NCong Wang <cong.wang@bytedance.com>
Link: https://lore.kernel.org/r/1630252681-71588-1-git-send-email-xiyuyang19@fudan.edu.cnSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

net/sched/sch_cbq.c

@@ -1614,7 +1614,7 @@ cbq_change_class(struct Qdisc *sch, u32 classid, u32 parentid, struct nlattr **t
 	err = tcf_block_get(&cl->block, &cl->filter_list, sch, extack);
 	if (err) {
 		kfree(cl);
-		return err;
+		goto failure;
 	}
 
 	if (tca[TCA_RATE]) {