[PATCH 4.14 281/496] net/sched: fix idr leak in the error path of tcf_act_police_init()

[Greg Kroah-Hartman]

4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Davide Caratti <dcaratti@xxxxxxxxxx>

[ Upstream commit 5bf7f8185f7c7112decdfe3d3e5c5d5e67f099a1 ]

tcf_act_police_init() can fail after the idr has been successfully
reserved (e.g., qdisc_get_rtab() may return NULL). When this happens,
subsequent attempts to configure a police rule using the same idr value
systematiclly fail with -ENOSPC:

 # tc action add action police rate 1000 burst 1000 drop index 100
 RTNETLINK answers: Cannot allocate memory
 We have an error talking to the kernel
 # tc action add action police rate 1000 burst 1000 drop index 100
 RTNETLINK answers: No space left on device
 We have an error talking to the kernel
 # tc action add action police rate 1000 burst 1000 drop index 100
 RTNETLINK answers: No space left on device
 ...

Fix this in the error path of tcf_act_police_init(), calling
tcf_idr_release() in place of tcf_idr_cleanup().

Fixes: 65a206c01e8e ("net/sched: Change act_api and act_xxx modules to use IDR")
Acked-by: Jamal Hadi Salim <jhs@xxxxxxxxxxxx>
Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/sched/act_police.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -194,7 +194,7 @@ failure:
 	qdisc_put_rtab(P_tab);
 	qdisc_put_rtab(R_tab);
 	if (ret == ACT_P_CREATED)
-		tcf_idr_cleanup(*a, est);
+		tcf_idr_release(*a, bind);
 	return err;
 }