Thread (4 messages) 4 messages, 4 authors, 2021-08-31

[PATCH] net: sched: Fix qdisc_rate_table refcount leak when get tcf_block failed

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STALE1866d LANDED

From: Xiyu Yang <hidden>
Date: 2021-08-29 15:58:41
Also in: lkml
Subsystem: networking [general], tc subsystem, the rest · Maintainers: "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds

Landed in mainline as c66070125837 on 2021-08-31.

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.

Signed-off-by: Xiyu Yang <redacted>
---
 net/sched/sch_cbq.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sched/sch_cbq.c b/net/sched/sch_cbq.c
index b79a7e27bb31..38a3a8394bbd 100644
--- a/net/sched/sch_cbq.c
+++ b/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]) {
-- 
2.7.4
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