From 0faa9cb5b3836a979864a6357e01d2046884ad52 Mon Sep 17 00:00:00 2001 From: Jamal Hadi Salim Date: Sun, 15 Jan 2017 10:14:06 -0500 Subject: [PATCH] net sched actions: fix refcnt when GETing of action after bind Demonstrating the issue: .. add a drop action $sudo $TC actions add action drop index 10 .. retrieve it $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 0 installed 29 sec used 29 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... bug 1 above: reference is two. Reference is actually 1 but we forget to subtract 1. ... do a GET again and we see the same issue try a few times and nothing changes ~$ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 0 installed 31 sec used 31 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... lets try to bind the action to a filter.. $ sudo $TC qdisc add dev lo ingress $ sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \ u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 10 ... and now a few GETs: $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 3 bind 1 installed 204 sec used 204 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 4 bind 1 installed 206 sec used 206 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 5 bind 1 installed 235 sec used 235 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 .... as can be observed the reference count keeps going up. After the fix $ sudo $TC actions add action drop index 10 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 1 bind 0 installed 4 sec used 4 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 1 bind 0 installed 6 sec used 6 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC qdisc add dev lo ingress $ sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \ u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 10 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 1 installed 32 sec used 32 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 1 installed 33 sec used 33 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 Fixes: aecc5cefc389 ("net sched actions: fix GETing actions") Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- net/sched/act_api.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 2095c83ce773..e10456ef6f7a 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -900,8 +900,6 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n, goto err; } act->order = i; - if (event == RTM_GETACTION) - act->tcfa_refcnt++; list_add_tail(&act->list, &actions); } @@ -914,7 +912,8 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n, return ret; } err: - tcf_action_destroy(&actions, 0); + if (event != RTM_GETACTION) + tcf_action_destroy(&actions, 0); return ret; }