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authorHannes Frederic Sowa <hannes@stressinduktion.org>2014-01-13 02:45:22 +0100
committerDavid S. Miller <davem@davemloft.net>2014-01-14 17:37:25 -0800
commit95f4a45de1a0f172b35451fc52283290adb21f6e (patch)
tree04574bc5a4f4b60133b3dbc72c5174a9f847b3b4
parent7c4b5175f65f31e0cd9867a6ddc3171007dfc110 (diff)
downloadlinux-95f4a45de1a0f172b35451fc52283290adb21f6e.tar.gz
net: avoid reference counter overflows on fib_rules in multicast forwarding
Bob Falken reported that after 4G packets, multicast forwarding stopped working. This was because of a rule reference counter overflow which freed the rule as soon as the overflow happend. This patch solves this by adding the FIB_LOOKUP_NOREF flag to fib_rules_lookup calls. This is safe even from non-rcu locked sections as in this case the flag only implies not taking a reference to the rule, which we don't need at all. Rules only hold references to the namespace, which are guaranteed to be available during the call of the non-rcu protected function reg_vif_xmit because of the interface reference which itself holds a reference to the net namespace. Fixes: f0ad0860d01e47 ("ipv4: ipmr: support multiple tables") Fixes: d1db275dd3f6e4 ("ipv6: ip6mr: support multiple tables") Reported-by: Bob Falken <NetFestivalHaveFun@gmx.com> Cc: Patrick McHardy <kaber@trash.net> Cc: Thomas Graf <tgraf@suug.ch> Cc: Julian Anastasov <ja@ssi.bg> Cc: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/ipmr.c7
-rw-r--r--net/ipv6/ip6mr.c7
2 files changed, 10 insertions, 4 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c
index 62212c772a4..1672409f5ba 100644
--- a/net/ipv4/ipmr.c
+++ b/net/ipv4/ipmr.c
@@ -157,9 +157,12 @@ static struct mr_table *ipmr_get_table(struct net *net, u32 id)
static int ipmr_fib_lookup(struct net *net, struct flowi4 *flp4,
struct mr_table **mrt)
{
- struct ipmr_result res;
- struct fib_lookup_arg arg = { .result = &res, };
int err;
+ struct ipmr_result res;
+ struct fib_lookup_arg arg = {
+ .result = &res,
+ .flags = FIB_LOOKUP_NOREF,
+ };
err = fib_rules_lookup(net->ipv4.mr_rules_ops,
flowi4_to_flowi(flp4), 0, &arg);
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index f365310bfcc..0eb4038a4d6 100644
--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -141,9 +141,12 @@ static struct mr6_table *ip6mr_get_table(struct net *net, u32 id)
static int ip6mr_fib_lookup(struct net *net, struct flowi6 *flp6,
struct mr6_table **mrt)
{
- struct ip6mr_result res;
- struct fib_lookup_arg arg = { .result = &res, };
int err;
+ struct ip6mr_result res;
+ struct fib_lookup_arg arg = {
+ .result = &res,
+ .flags = FIB_LOOKUP_NOREF,
+ };
err = fib_rules_lookup(net->ipv6.mr6_rules_ops,
flowi6_to_flowi(flp6), 0, &arg);