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)
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>
3 files changed, 7 insertions, 2 deletions
diff --git a/include/net/psample.h b/include/net/psample.h
index 37a4df2325b2..6b578ce69cd8 100644
--- a/include/net/psample.h
+++ b/include/net/psample.h
@@ -11,6 +11,7 @@ struct psample_group {
u32 group_num;
u32 refcount;
u32 seq;
+ struct rcu_head rcu;
struct psample_group *psample_group_get(struct net *net, u32 group_num);
diff --git a/net/psample/psample.c b/net/psample/psample.c
index 841f198ea1a8..66e4b61a350d 100644
--- a/net/psample/psample.c
+++ b/net/psample/psample.c
@@ -154,7 +154,7 @@ static void psample_group_destroy(struct psample_group *group)
psample_group_notify(group, PSAMPLE_CMD_DEL_GROUP);
- kfree(group);
+ kfree_rcu(group, rcu);
static struct psample_group *
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)