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 <[email protected]>
---
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
On Sun, 29 Aug 2021 23:58:01 +0800 Xiyu Yang wrote:
> 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 <[email protected]>
Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
On Mon, Aug 30, 2021 at 11:05 AM Jakub Kicinski <[email protected]> wrote:
>
> On Sun, 29 Aug 2021 23:58:01 +0800 Xiyu Yang wrote:
> > 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 <[email protected]>
>
> Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Reviewed-by: Cong Wang <[email protected]>
Thanks.
Hello:
This patch was applied to netdev/net-next.git (refs/heads/master):
On Sun, 29 Aug 2021 23:58:01 +0800 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- net: sched: Fix qdisc_rate_table refcount leak when get tcf_block failed
https://git.kernel.org/netdev/net-next/c/c66070125837
You are awesome, thank you!
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