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authorDavid Windsor <dwindsor@gmail.com>2017-01-23 22:24:29 -0500
committerPablo Neira Ayuso <pablo@netfilter.org>2017-02-02 14:31:57 +0100
commit90c1aff702d449a1a248c4829d51c0bc677f968e (patch)
tree95949a5240fb0a29d5dd16ec9df93730d8452b31 /net/netfilter/ipvs
parenta9e419dc7be6997409dca6d1b9daf3cc7046902f (diff)
ipvs: free ip_vs_dest structs when refcnt=0
Currently, the ip_vs_dest cache frees ip_vs_dest objects when their reference count becomes < 0. Aside from not being semantically sound, this is problematic for the new type refcount_t, which will be introduced shortly in a separate patch. refcount_t is the new kernel type for holding reference counts, and provides overflow protection and a constrained interface relative to atomic_t (the type currently being used for kernel reference counts). Per Julian Anastasov: "The problem is that dest_trash currently holds deleted dests (unlinked from RCU lists) with refcnt=0." Changing dest_trash to hold dest with refcnt=1 will allow us to free ip_vs_dest structs when their refcnt=0, in ip_vs_dest_put_and_free(). Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/netfilter/ipvs')
-rw-r--r--net/netfilter/ipvs/ip_vs_ctl.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 55e0169caa4c..5fc4836e7c79 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -711,7 +711,6 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, int dest_af,
dest->vport == svc->port))) {
/* HIT */
list_del(&dest->t_list);
- ip_vs_dest_hold(dest);
goto out;
}
}
@@ -741,7 +740,7 @@ static void ip_vs_dest_free(struct ip_vs_dest *dest)
* When the ip_vs_control_clearup is activated by ipvs module exit,
* the service tables must have been flushed and all the connections
* are expired, and the refcnt of each destination in the trash must
- * be 0, so we simply release them here.
+ * be 1, so we simply release them here.
*/
static void ip_vs_trash_cleanup(struct netns_ipvs *ipvs)
{
@@ -1080,11 +1079,10 @@ static void __ip_vs_del_dest(struct netns_ipvs *ipvs, struct ip_vs_dest *dest,
if (list_empty(&ipvs->dest_trash) && !cleanup)
mod_timer(&ipvs->dest_trash_timer,
jiffies + (IP_VS_DEST_TRASH_PERIOD >> 1));
- /* dest lives in trash without reference */
+ /* dest lives in trash with reference */
list_add(&dest->t_list, &ipvs->dest_trash);
dest->idle_start = 0;
spin_unlock_bh(&ipvs->dest_trash_lock);
- ip_vs_dest_put(dest);
}
@@ -1160,7 +1158,7 @@ static void ip_vs_dest_trash_expire(unsigned long data)
spin_lock(&ipvs->dest_trash_lock);
list_for_each_entry_safe(dest, next, &ipvs->dest_trash, t_list) {
- if (atomic_read(&dest->refcnt) > 0)
+ if (atomic_read(&dest->refcnt) > 1)
continue;
if (dest->idle_start) {
if (time_before(now, dest->idle_start +