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authorMartin KaFai Lau <kafai@fb.com>2015-09-16 00:30:07 +0300
committerDavid S. Miller <davem@davemloft.net>2015-09-16 00:53:05 +0300
commitcdf3464e6c6bd764277cbbe992cd12da735b92fb (patch)
tree53e75a7f94aba7ced57ae7f2b527bce0d463a629 /net/ipv6/ip6_gre.c
parentf230d1e891ba1da5953460516960894154f265db (diff)
downloadlinux-cdf3464e6c6bd764277cbbe992cd12da735b92fb.tar.xz
ipv6: Fix dst_entry refcnt bugs in ip6_tunnel
Problems in the current dst_entry cache in the ip6_tunnel: 1. ip6_tnl_dst_set is racy. There is no lock to protect it: - One major problem is that the dst refcnt gets messed up. F.e. the same dst_cache can be released multiple times and then triggering the infamous dst refcnt < 0 warning message. - Another issue is the inconsistency between dst_cache and dst_cookie. It can be reproduced by adding and removing the ip6gre tunnel while running a super_netperf TCP_CRR test. 2. ip6_tnl_dst_get does not take the dst refcnt before returning the dst. This patch: 1. Create a percpu dst_entry cache in ip6_tnl 2. Use a spinlock to protect the dst_cache operations 3. ip6_tnl_dst_get always takes the dst refcnt before returning Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ip6_gre.c')
-rw-r--r--net/ipv6/ip6_gre.c38
1 files changed, 22 insertions, 16 deletions
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 24f5dd8f76a8..646512488c28 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -637,17 +637,17 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
dst = ip6_tnl_dst_get(tunnel);
if (!dst) {
- ndst = ip6_route_output(net, NULL, fl6);
+ dst = ip6_route_output(net, NULL, fl6);
- if (ndst->error)
+ if (dst->error)
goto tx_err_link_failure;
- ndst = xfrm_lookup(net, ndst, flowi6_to_flowi(fl6), NULL, 0);
- if (IS_ERR(ndst)) {
- err = PTR_ERR(ndst);
- ndst = NULL;
+ dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), NULL, 0);
+ if (IS_ERR(dst)) {
+ err = PTR_ERR(dst);
+ dst = NULL;
goto tx_err_link_failure;
}
- dst = ndst;
+ ndst = dst;
}
tdev = dst->dev;
@@ -702,12 +702,9 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
skb = new_skb;
}
- if (fl6->flowi6_mark) {
- skb_dst_set(skb, dst);
- ndst = NULL;
- } else {
- skb_dst_set_noref(skb, dst);
- }
+ if (!fl6->flowi6_mark && ndst)
+ ip6_tnl_dst_set(tunnel, ndst);
+ skb_dst_set(skb, dst);
proto = NEXTHDR_GRE;
if (encap_limit >= 0) {
@@ -762,14 +759,12 @@ static netdev_tx_t ip6gre_xmit2(struct sk_buff *skb,
skb_set_inner_protocol(skb, protocol);
ip6tunnel_xmit(NULL, skb, dev);
- if (ndst)
- ip6_tnl_dst_set(tunnel, ndst);
return 0;
tx_err_link_failure:
stats->tx_carrier_errors++;
dst_link_failure(skb);
tx_err_dst_release:
- dst_release(ndst);
+ dst_release(dst);
return err;
}
@@ -1223,6 +1218,9 @@ static const struct net_device_ops ip6gre_netdev_ops = {
static void ip6gre_dev_free(struct net_device *dev)
{
+ struct ip6_tnl *t = netdev_priv(dev);
+
+ ip6_tnl_dst_destroy(t);
free_percpu(dev->tstats);
free_netdev(dev);
}
@@ -1248,6 +1246,7 @@ static void ip6gre_tunnel_setup(struct net_device *dev)
static int ip6gre_tunnel_init_common(struct net_device *dev)
{
struct ip6_tnl *tunnel;
+ int ret;
tunnel = netdev_priv(dev);
@@ -1259,6 +1258,13 @@ static int ip6gre_tunnel_init_common(struct net_device *dev)
if (!dev->tstats)
return -ENOMEM;
+ ret = ip6_tnl_dst_init(tunnel);
+ if (ret) {
+ free_percpu(dev->tstats);
+ dev->tstats = NULL;
+ return ret;
+ }
+
return 0;
}