From dbf47a2a094edf58983265e323ca4bdcdb58b5ee Mon Sep 17 00:00:00 2001 From: Vlad Buslov Date: Tue, 27 Aug 2019 21:49:38 +0300 Subject: 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 Signed-off-by: David S. Miller --- include/net/psample.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/net/psample.h') 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); -- cgit v1.2.3