path: root/net/sched/act_sample.c
diff options
authorVlad Buslov <vladbu@mellanox.com>2019-08-27 21:49:38 +0300
committerDavid S. Miller <davem@davemloft.net>2019-08-28 15:53:51 -0700
commitdbf47a2a094edf58983265e323ca4bdcdb58b5ee (patch)
tree4d67881165f57063cadc0456b7c7e5c8be0b5090 /net/sched/act_sample.c
parentibmvnic: Do not process reset during or after device removal (diff)
net: sched: act_sample: fix psample group handling on overwrite
Action sample doesn't properly handle psample_group pointer in overwrite case. Following issues need to be fixed: - In tcf_sample_init() function RCU_INIT_POINTER() is used to set s->psample_group, even though we neither setting the pointer to NULL, nor preventing concurrent readers from accessing the pointer in some way. Use rcu_swap_protected() instead to safely reset the pointer. - Old value of s->psample_group is not released or deallocated in any way, which results resource leak. Use psample_group_put() on non-NULL value obtained with rcu_swap_protected(). - The function psample_group_put() that released reference to struct psample_group pointed by rcu-pointer s->psample_group doesn't respect rcu grace period when deallocating it. Extend struct psample_group with rcu head and use kfree_rcu when freeing it. Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action") Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to '')
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 7eff363f9f03..10229124a992 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -102,13 +102,17 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
s->rate = rate;
s->psample_group_num = psample_group_num;
- RCU_INIT_POINTER(s->psample_group, psample_group);
+ rcu_swap_protected(s->psample_group, psample_group,
+ lockdep_is_held(&s->tcf_lock));
s->truncate = true;
s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
+ if (psample_group)
+ psample_group_put(psample_group);
if (goto_ch)