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authorHannes Frederic Sowa <hannes@stressinduktion.org>2015-01-26 15:11:17 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-02-26 17:48:48 -0800
commit650a7901c0fe0c3b0e5d9c1c945f140058585a6f (patch)
tree3759f964cb70c7a8b8cb2c6a652096bea1a9a194 /net
parent688ba993d1b7e3c84b1a87f39cd14b01b4716306 (diff)
downloadlinux-linaro-stable-650a7901c0fe0c3b0e5d9c1c945f140058585a6f.tar.gz
ipv6: replacing a rt6_info needs to purge possible propagated rt6_infos too
[ Upstream commit 6e9e16e6143b725662e47026a1d0f270721cdd24 ] Lubomir Rintel reported that during replacing a route the interface reference counter isn't correctly decremented. To quote bug <https://bugzilla.kernel.org/show_bug.cgi?id=91941>: | [root@rhel7-5 lkundrak]# sh -x lal | + ip link add dev0 type dummy | + ip link set dev0 up | + ip link add dev1 type dummy | + ip link set dev1 up | + ip addr add 2001:db8:8086::2/64 dev dev0 | + ip route add 2001:db8:8086::/48 dev dev0 proto static metric 20 | + ip route add 2001:db8:8088::/48 dev dev1 proto static metric 10 | + ip route replace 2001:db8:8086::/48 dev dev1 proto static metric 20 | + ip link del dev0 type dummy | Message from syslogd@rhel7-5 at Jan 23 10:54:41 ... | kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2 | | Message from syslogd@rhel7-5 at Jan 23 10:54:51 ... | kernel:unregister_netdevice: waiting for dev0 to become free. Usage count = 2 During replacement of a rt6_info we must walk all parent nodes and check if the to be replaced rt6_info got propagated. If so, replace it with an alive one. Fixes: 4a287eba2de3957 ("IPv6 routing, NLM_F_* flag support: REPLACE and EXCL flags support, warn about missing CREATE flag") Reported-by: Lubomir Rintel <lkundrak@v3.sk> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Tested-by: Lubomir Rintel <lkundrak@v3.sk> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/ip6_fib.c45
1 files changed, 26 insertions, 19 deletions
diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 009c9620f442..ceeb9458bb60 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -638,6 +638,29 @@ static inline bool rt6_qualify_for_ecmp(struct rt6_info *rt)
RTF_GATEWAY;
}
+static void fib6_purge_rt(struct rt6_info *rt, struct fib6_node *fn,
+ struct net *net)
+{
+ if (atomic_read(&rt->rt6i_ref) != 1) {
+ /* This route is used as dummy address holder in some split
+ * nodes. It is not leaked, but it still holds other resources,
+ * which must be released in time. So, scan ascendant nodes
+ * and replace dummy references to this route with references
+ * to still alive ones.
+ */
+ while (fn) {
+ if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
+ fn->leaf = fib6_find_prefix(net, fn);
+ atomic_inc(&fn->leaf->rt6i_ref);
+ rt6_release(rt);
+ }
+ fn = fn->parent;
+ }
+ /* No more references are possible at this point. */
+ BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
+ }
+}
+
/*
* Insert routing information in a node.
*/
@@ -775,11 +798,12 @@ add:
rt->dst.rt6_next = iter->dst.rt6_next;
atomic_inc(&rt->rt6i_ref);
inet6_rt_notify(RTM_NEWROUTE, rt, info);
- rt6_release(iter);
if (!(fn->fn_flags & RTN_RTINFO)) {
info->nl_net->ipv6.rt6_stats->fib_route_nodes++;
fn->fn_flags |= RTN_RTINFO;
}
+ fib6_purge_rt(iter, fn, info->nl_net);
+ rt6_release(iter);
}
return 0;
@@ -1284,24 +1308,7 @@ static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
fn = fib6_repair_tree(net, fn);
}
- if (atomic_read(&rt->rt6i_ref) != 1) {
- /* This route is used as dummy address holder in some split
- * nodes. It is not leaked, but it still holds other resources,
- * which must be released in time. So, scan ascendant nodes
- * and replace dummy references to this route with references
- * to still alive ones.
- */
- while (fn) {
- if (!(fn->fn_flags & RTN_RTINFO) && fn->leaf == rt) {
- fn->leaf = fib6_find_prefix(net, fn);
- atomic_inc(&fn->leaf->rt6i_ref);
- rt6_release(rt);
- }
- fn = fn->parent;
- }
- /* No more references are possible at this point. */
- BUG_ON(atomic_read(&rt->rt6i_ref) != 1);
- }
+ fib6_purge_rt(rt, fn, net);
inet6_rt_notify(RTM_DELROUTE, rt, info);
rt6_release(rt);