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authorEric Dumazet <edumazet@google.com>2014-09-04 09:21:56 +0400
committerDavid S. Miller <davem@davemloft.net>2014-09-06 04:15:50 +0400
commitcaa415270c732505240bb60171c44a7838c555e8 (patch)
treecd44cd81f85c3904340f5cef1a359e2ae97a0c20 /net/ipv4/route.c
parent29abe2fda54f8e16ecff5d76d96325f31508d5ba (diff)
downloadlinux-caa415270c732505240bb60171c44a7838c555e8.tar.xz
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/route.c')
-rw-r--r--net/ipv4/route.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index eaa4b000c7b4..44b0cbdd76f1 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -628,12 +628,12 @@ static void update_or_create_fnhe(struct fib_nh *nh, __be32 daddr, __be32 gw,
spin_lock_bh(&fnhe_lock);
- hash = nh->nh_exceptions;
+ hash = rcu_dereference(nh->nh_exceptions);
if (!hash) {
hash = kzalloc(FNHE_HASH_SIZE * sizeof(*hash), GFP_ATOMIC);
if (!hash)
goto out_unlock;
- nh->nh_exceptions = hash;
+ rcu_assign_pointer(nh->nh_exceptions, hash);
}
hash += hval;
@@ -1242,7 +1242,7 @@ static unsigned int ipv4_mtu(const struct dst_entry *dst)
static struct fib_nh_exception *find_exception(struct fib_nh *nh, __be32 daddr)
{
- struct fnhe_hash_bucket *hash = nh->nh_exceptions;
+ struct fnhe_hash_bucket *hash = rcu_dereference(nh->nh_exceptions);
struct fib_nh_exception *fnhe;
u32 hval;