diff options
| author | Eric Dumazet <edumazet@google.com> | 2014-09-03 22:21:56 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-09-05 17:15:50 -0700 |
| commit | caa415270c732505240bb60171c44a7838c555e8 (patch) | |
| tree | cd44cd81f85c3904340f5cef1a359e2ae97a0c20 /net/ipv4/fib_semantics.c | |
| parent | 29abe2fda54f8e16ecff5d76d96325f31508d5ba (diff) | |
ipv4: fix a race in update_or_create_fnhe()
nh_exceptions is effectively used under rcu, but lacks proper
barriers. Between kzalloc() and setting of nh->nh_exceptions(),
we need a proper memory barrier.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 4895c771c7f00 ("ipv4: Add FIB nexthop exceptions.")
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/fib_semantics.c')
| -rw-r--r-- | net/ipv4/fib_semantics.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c index b10cd43a4722..5b6efb3d2308 100644 --- a/net/ipv4/fib_semantics.c +++ b/net/ipv4/fib_semantics.c @@ -157,9 +157,12 @@ static void rt_fibinfo_free(struct rtable __rcu **rtp) static void free_nh_exceptions(struct fib_nh *nh) { - struct fnhe_hash_bucket *hash = nh->nh_exceptions; + struct fnhe_hash_bucket *hash; int i; + hash = rcu_dereference_protected(nh->nh_exceptions, 1); + if (!hash) + return; for (i = 0; i < FNHE_HASH_SIZE; i++) { struct fib_nh_exception *fnhe; @@ -205,8 +208,7 @@ static void free_fib_info_rcu(struct rcu_head *head) change_nexthops(fi) { if (nexthop_nh->nh_dev) dev_put(nexthop_nh->nh_dev); - if (nexthop_nh->nh_exceptions) - free_nh_exceptions(nexthop_nh); + free_nh_exceptions(nexthop_nh); rt_fibinfo_free_cpus(nexthop_nh->nh_pcpu_rth_output); rt_fibinfo_free(&nexthop_nh->nh_rth_input); } endfor_nexthops(fi); |