From c16526a7b99c1c28e9670a8c8e3dbcf741bb32be Mon Sep 17 00:00:00 2001 From: Simon Kirby Date: Sat, 10 Aug 2013 01:26:18 -0700 Subject: ipvs: fix overflow on dest weight multiply Schedulers such as lblc and lblcr require the weight to be as high as the maximum number of active connections. In commit b552f7e3a9524abcbcdf ("ipvs: unify the formula to estimate the overhead of processing connections"), the consideration of inactconns and activeconns was cleaned up to always count activeconns as 256 times more important than inactconns. In cases where 3000 or more connections are expected, a weight of 3000 * 256 * 3000 connections overflows the 32-bit signed result used to determine if rescheduling is required. On amd64, this merely changes the multiply and comparison instructions to 64-bit. On x86, a 64-bit result is already present from imull, so only a few more comparison instructions are emitted. Signed-off-by: Simon Kirby Acked-by: Julian Anastasov Signed-off-by: Simon Horman --- include/net/ip_vs.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/net/ip_vs.h') diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index f0d70f066f3d..fe782ed2fe72 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -1649,7 +1649,7 @@ static inline void ip_vs_conn_drop_conntrack(struct ip_vs_conn *cp) /* CONFIG_IP_VS_NFCT */ #endif -static inline unsigned int +static inline int ip_vs_dest_conn_overhead(struct ip_vs_dest *dest) { /* -- cgit v1.2.3 From bcbde4c0a7556cca72874c5e1efa4dccb5198a2b Mon Sep 17 00:00:00 2001 From: Julian Anastasov Date: Thu, 12 Sep 2013 11:21:07 +0300 Subject: ipvs: make the service replacement more robust commit 578bc3ef1e473a ("ipvs: reorganize dest trash") added IP_VS_DEST_STATE_REMOVING flag and RCU callback named ip_vs_dest_wait_readers() to keep dests and services after removal for at least a RCU grace period. But we have the following corner cases: - we can not reuse the same dest if its service is removed while IP_VS_DEST_STATE_REMOVING is still set because another dest removal in the first grace period can not extend this period. It can happen when ipvsadm -C && ipvsadm -R is used. - dest->svc can be replaced but ip_vs_in_stats() and ip_vs_out_stats() have no explicit read memory barriers when accessing dest->svc. It can happen that dest->svc was just freed (replaced) while we use it to update the stats. We solve the problems as follows: - IP_VS_DEST_STATE_REMOVING is removed and we ensure a fixed idle period for the dest (IP_VS_DEST_TRASH_PERIOD). idle_start will remember when for first time after deletion we noticed dest->refcnt=0. Later, the connections can grab a reference while in RCU grace period but if refcnt becomes 0 we can safely free the dest and its svc. - dest->svc becomes RCU pointer. As result, we add explicit RCU locking in ip_vs_in_stats() and ip_vs_out_stats(). - __ip_vs_unbind_svc is renamed to __ip_vs_svc_put(), it now can free the service immediately or after a RCU grace period. dest->svc is not set to NULL anymore. As result, unlinked dests and their services are freed always after IP_VS_DEST_TRASH_PERIOD period, unused services are freed after a RCU grace period. Signed-off-by: Julian Anastasov Signed-off-by: Simon Horman --- include/net/ip_vs.h | 7 +--- net/netfilter/ipvs/ip_vs_core.c | 12 +++++- net/netfilter/ipvs/ip_vs_ctl.c | 86 +++++++++++++++++------------------------ 3 files changed, 47 insertions(+), 58 deletions(-) (limited to 'include/net/ip_vs.h') diff --git a/include/net/ip_vs.h b/include/net/ip_vs.h index fe782ed2fe72..9c4d37ec45a1 100644 --- a/include/net/ip_vs.h +++ b/include/net/ip_vs.h @@ -723,8 +723,6 @@ struct ip_vs_dest_dst { struct rcu_head rcu_head; }; -/* In grace period after removing */ -#define IP_VS_DEST_STATE_REMOVING 0x01 /* * The real server destination forwarding entry * with ip address, port number, and so on. @@ -742,7 +740,7 @@ struct ip_vs_dest { atomic_t refcnt; /* reference counter */ struct ip_vs_stats stats; /* statistics */ - unsigned long state; /* state flags */ + unsigned long idle_start; /* start time, jiffies */ /* connection counters and thresholds */ atomic_t activeconns; /* active connections */ @@ -756,14 +754,13 @@ struct ip_vs_dest { struct ip_vs_dest_dst __rcu *dest_dst; /* cached dst info */ /* for virtual service */ - struct ip_vs_service *svc; /* service it belongs to */ + struct ip_vs_service __rcu *svc; /* service it belongs to */ __u16 protocol; /* which protocol (TCP/UDP) */ __be16 vport; /* virtual port number */ union nf_inet_addr vaddr; /* virtual IP address */ __u32 vfwmark; /* firewall mark of service */ struct list_head t_list; /* in dest_trash */ - struct rcu_head rcu_head; unsigned int in_rs_table:1; /* we are in rs_table */ }; diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index 4f69e83ff836..74fd00c27210 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -116,6 +116,7 @@ ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb) if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) { struct ip_vs_cpu_stats *s; + struct ip_vs_service *svc; s = this_cpu_ptr(dest->stats.cpustats); s->ustats.inpkts++; @@ -123,11 +124,14 @@ ip_vs_in_stats(struct ip_vs_conn *cp, struct sk_buff *skb) s->ustats.inbytes += skb->len; u64_stats_update_end(&s->syncp); - s = this_cpu_ptr(dest->svc->stats.cpustats); + rcu_read_lock(); + svc = rcu_dereference(dest->svc); + s = this_cpu_ptr(svc->stats.cpustats); s->ustats.inpkts++; u64_stats_update_begin(&s->syncp); s->ustats.inbytes += skb->len; u64_stats_update_end(&s->syncp); + rcu_read_unlock(); s = this_cpu_ptr(ipvs->tot_stats.cpustats); s->ustats.inpkts++; @@ -146,6 +150,7 @@ ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb) if (dest && (dest->flags & IP_VS_DEST_F_AVAILABLE)) { struct ip_vs_cpu_stats *s; + struct ip_vs_service *svc; s = this_cpu_ptr(dest->stats.cpustats); s->ustats.outpkts++; @@ -153,11 +158,14 @@ ip_vs_out_stats(struct ip_vs_conn *cp, struct sk_buff *skb) s->ustats.outbytes += skb->len; u64_stats_update_end(&s->syncp); - s = this_cpu_ptr(dest->svc->stats.cpustats); + rcu_read_lock(); + svc = rcu_dereference(dest->svc); + s = this_cpu_ptr(svc->stats.cpustats); s->ustats.outpkts++; u64_stats_update_begin(&s->syncp); s->ustats.outbytes += skb->len; u64_stats_update_end(&s->syncp); + rcu_read_unlock(); s = this_cpu_ptr(ipvs->tot_stats.cpustats); s->ustats.outpkts++; diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c index c8148e487386..a3df9bddc4f7 100644 --- a/net/netfilter/ipvs/ip_vs_ctl.c +++ b/net/netfilter/ipvs/ip_vs_ctl.c @@ -460,7 +460,7 @@ static inline void __ip_vs_bind_svc(struct ip_vs_dest *dest, struct ip_vs_service *svc) { atomic_inc(&svc->refcnt); - dest->svc = svc; + rcu_assign_pointer(dest->svc, svc); } static void ip_vs_service_free(struct ip_vs_service *svc) @@ -470,18 +470,25 @@ static void ip_vs_service_free(struct ip_vs_service *svc) kfree(svc); } -static void -__ip_vs_unbind_svc(struct ip_vs_dest *dest) +static void ip_vs_service_rcu_free(struct rcu_head *head) { - struct ip_vs_service *svc = dest->svc; + struct ip_vs_service *svc; + + svc = container_of(head, struct ip_vs_service, rcu_head); + ip_vs_service_free(svc); +} - dest->svc = NULL; +static void __ip_vs_svc_put(struct ip_vs_service *svc, bool do_delay) +{ if (atomic_dec_and_test(&svc->refcnt)) { IP_VS_DBG_BUF(3, "Removing service %u/%s:%u\n", svc->fwmark, IP_VS_DBG_ADDR(svc->af, &svc->addr), ntohs(svc->port)); - ip_vs_service_free(svc); + if (do_delay) + call_rcu(&svc->rcu_head, ip_vs_service_rcu_free); + else + ip_vs_service_free(svc); } } @@ -667,11 +674,6 @@ ip_vs_trash_get_dest(struct ip_vs_service *svc, const union nf_inet_addr *daddr, IP_VS_DBG_ADDR(svc->af, &dest->addr), ntohs(dest->port), atomic_read(&dest->refcnt)); - /* We can not reuse dest while in grace period - * because conns still can use dest->svc - */ - if (test_bit(IP_VS_DEST_STATE_REMOVING, &dest->state)) - continue; if (dest->af == svc->af && ip_vs_addr_equal(svc->af, &dest->addr, daddr) && dest->port == dport && @@ -697,8 +699,10 @@ out: static void ip_vs_dest_free(struct ip_vs_dest *dest) { + struct ip_vs_service *svc = rcu_dereference_protected(dest->svc, 1); + __ip_vs_dst_cache_reset(dest); - __ip_vs_unbind_svc(dest); + __ip_vs_svc_put(svc, false); free_percpu(dest->stats.cpustats); kfree(dest); } @@ -771,6 +775,7 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest, struct ip_vs_dest_user_kern *udest, int add) { struct netns_ipvs *ipvs = net_ipvs(svc->net); + struct ip_vs_service *old_svc; struct ip_vs_scheduler *sched; int conn_flags; @@ -792,13 +797,14 @@ __ip_vs_update_dest(struct ip_vs_service *svc, struct ip_vs_dest *dest, atomic_set(&dest->conn_flags, conn_flags); /* bind the service */ - if (!dest->svc) { + old_svc = rcu_dereference_protected(dest->svc, 1); + if (!old_svc) { __ip_vs_bind_svc(dest, svc); } else { - if (dest->svc != svc) { - __ip_vs_unbind_svc(dest); + if (old_svc != svc) { ip_vs_zero_stats(&dest->stats); __ip_vs_bind_svc(dest, svc); + __ip_vs_svc_put(old_svc, true); } } @@ -998,16 +1004,6 @@ ip_vs_edit_dest(struct ip_vs_service *svc, struct ip_vs_dest_user_kern *udest) return 0; } -static void ip_vs_dest_wait_readers(struct rcu_head *head) -{ - struct ip_vs_dest *dest = container_of(head, struct ip_vs_dest, - rcu_head); - - /* End of grace period after unlinking */ - clear_bit(IP_VS_DEST_STATE_REMOVING, &dest->state); -} - - /* * Delete a destination (must be already unlinked from the service) */ @@ -1023,20 +1019,16 @@ static void __ip_vs_del_dest(struct net *net, struct ip_vs_dest *dest, */ ip_vs_rs_unhash(dest); - if (!cleanup) { - set_bit(IP_VS_DEST_STATE_REMOVING, &dest->state); - call_rcu(&dest->rcu_head, ip_vs_dest_wait_readers); - } - spin_lock_bh(&ipvs->dest_trash_lock); IP_VS_DBG_BUF(3, "Moving dest %s:%u into trash, dest->refcnt=%d\n", IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port), atomic_read(&dest->refcnt)); if (list_empty(&ipvs->dest_trash) && !cleanup) mod_timer(&ipvs->dest_trash_timer, - jiffies + IP_VS_DEST_TRASH_PERIOD); + jiffies + (IP_VS_DEST_TRASH_PERIOD >> 1)); /* dest lives in trash without 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); } @@ -1108,24 +1100,30 @@ static void ip_vs_dest_trash_expire(unsigned long data) struct net *net = (struct net *) data; struct netns_ipvs *ipvs = net_ipvs(net); struct ip_vs_dest *dest, *next; + unsigned long now = jiffies; spin_lock(&ipvs->dest_trash_lock); list_for_each_entry_safe(dest, next, &ipvs->dest_trash, t_list) { - /* Skip if dest is in grace period */ - if (test_bit(IP_VS_DEST_STATE_REMOVING, &dest->state)) - continue; if (atomic_read(&dest->refcnt) > 0) continue; + if (dest->idle_start) { + if (time_before(now, dest->idle_start + + IP_VS_DEST_TRASH_PERIOD)) + continue; + } else { + dest->idle_start = max(1UL, now); + continue; + } IP_VS_DBG_BUF(3, "Removing destination %u/%s:%u from trash\n", dest->vfwmark, - IP_VS_DBG_ADDR(dest->svc->af, &dest->addr), + IP_VS_DBG_ADDR(dest->af, &dest->addr), ntohs(dest->port)); list_del(&dest->t_list); ip_vs_dest_free(dest); } if (!list_empty(&ipvs->dest_trash)) mod_timer(&ipvs->dest_trash_timer, - jiffies + IP_VS_DEST_TRASH_PERIOD); + jiffies + (IP_VS_DEST_TRASH_PERIOD >> 1)); spin_unlock(&ipvs->dest_trash_lock); } @@ -1320,14 +1318,6 @@ out: return ret; } -static void ip_vs_service_rcu_free(struct rcu_head *head) -{ - struct ip_vs_service *svc; - - svc = container_of(head, struct ip_vs_service, rcu_head); - ip_vs_service_free(svc); -} - /* * Delete a service from the service list * - The service must be unlinked, unlocked and not referenced! @@ -1376,13 +1366,7 @@ static void __ip_vs_del_service(struct ip_vs_service *svc, bool cleanup) /* * Free the service if nobody refers to it */ - if (atomic_dec_and_test(&svc->refcnt)) { - IP_VS_DBG_BUF(3, "Removing service %u/%s:%u\n", - svc->fwmark, - IP_VS_DBG_ADDR(svc->af, &svc->addr), - ntohs(svc->port)); - call_rcu(&svc->rcu_head, ip_vs_service_rcu_free); - } + __ip_vs_svc_put(svc, true); /* decrease the module use count */ ip_vs_use_count_dec(); -- cgit v1.2.3