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| author | David Windsor <dwindsor@gmail.com> | 2017-01-23 22:24:29 -0500 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-02-02 14:31:57 +0100 |
| commit | 90c1aff702d449a1a248c4829d51c0bc677f968e (patch) | |
| tree | 95949a5240fb0a29d5dd16ec9df93730d8452b31 /net/netfilter | |
| parent | a9e419dc7be6997409dca6d1b9daf3cc7046902f (diff) | |
| download | linux-90c1aff702d449a1a248c4829d51c0bc677f968e.tar.gz linux-90c1aff702d449a1a248c4829d51c0bc677f968e.tar.xz | |
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')
| -rw-r--r-- | net/netfilter/ipvs/ip_vs_ctl.c | 8 |
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 + |