diff options
author | Julian Anastasov <ja@ssi.bg> | 2015-06-29 21:51:40 +0300 |
---|---|---|
committer | Simon Horman <horms@verge.net.au> | 2015-07-14 16:41:27 +0900 |
commit | 05f00505a89acd21f5d0d20f5797dfbc4cf85243 (patch) | |
tree | 9e4948698b71fcec2dc3b233c22893efded4c16b /net/netfilter/ipvs/ip_vs_core.c | |
parent | 4754957f04f5f368792a0eb7dab0ae89fb93dcfd (diff) |
ipvs: fix crash if scheduler is changed
I overlooked the svc->sched_data usage from schedulers
when the services were converted to RCU in 3.10. Now
the rare ipvsadm -E command can change the scheduler
but due to the reverse order of ip_vs_bind_scheduler
and ip_vs_unbind_scheduler we provide new sched_data
to the old scheduler resulting in a crash.
To fix it without changing the scheduler methods we
have to use synchronize_rcu() only for the editing case.
It means all svc->scheduler readers should expect a
NULL value. To avoid breakage for the service listing
and ipvsadm -R we can use the "none" name to indicate
that scheduler is not assigned, a state when we drop
new connections.
Reported-by: Alexander Vasiliev <a.vasylev@404-group.com>
Fixes: ceec4c381681 ("ipvs: convert services to rcu")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Diffstat (limited to 'net/netfilter/ipvs/ip_vs_core.c')
-rw-r--r-- | net/netfilter/ipvs/ip_vs_core.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c index 5d2b806a862e..38fbc194b9cb 100644 --- a/net/netfilter/ipvs/ip_vs_core.c +++ b/net/netfilter/ipvs/ip_vs_core.c @@ -319,7 +319,13 @@ ip_vs_sched_persist(struct ip_vs_service *svc, * return *ignored=0 i.e. ICMP and NF_DROP */ sched = rcu_dereference(svc->scheduler); - dest = sched->schedule(svc, skb, iph); + if (sched) { + /* read svc->sched_data after svc->scheduler */ + smp_rmb(); + dest = sched->schedule(svc, skb, iph); + } else { + dest = NULL; + } if (!dest) { IP_VS_DBG(1, "p-schedule: no dest found.\n"); kfree(param.pe_data); @@ -467,7 +473,13 @@ ip_vs_schedule(struct ip_vs_service *svc, struct sk_buff *skb, } sched = rcu_dereference(svc->scheduler); - dest = sched->schedule(svc, skb, iph); + if (sched) { + /* read svc->sched_data after svc->scheduler */ + smp_rmb(); + dest = sched->schedule(svc, skb, iph); + } else { + dest = NULL; + } if (dest == NULL) { IP_VS_DBG(1, "Schedule: no dest found.\n"); return NULL; |