[PATCH 3.11 46/66] ipv6: probe routes asynchronous in rt6_probe

Greg Kroah-Hartman
2013-11-01T22:17:59Z

From: Hannes Frederic Sowa <hannes@stressinduktion.org>

[ Upstream commit c2f17e827b419918c856131f592df9521e1a38e3 ]

Routes need to be probed asynchronous otherwise the call stack gets
exhausted when the kernel attemps to deliver another skb inline, like
e.g. xt_TEE does, and we probe at the same time.

We update neigh->updated still at once, otherwise we would send to
many probes.

Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/route.c | 38 +++++++++++++++++++++++++++++++-------
1 file changed, 31 insertions(+), 7 deletions(-)

--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -477,6 +477,24 @@ out:
}

#ifdef CONFIG_IPV6_ROUTER_PREF
+struct __rt6_probe_work {
+ struct work_struct work;
+ struct in6_addr target;
+ struct net_device *dev;
+};
+
+static void rt6_probe_deferred(struct work_struct *w)
+{
+ struct in6_addr mcaddr;
+ struct __rt6_probe_work *work =
+ container_of(w, struct __rt6_probe_work, work);
+
+ addrconf_addr_solict_mult(&work->target, &mcaddr);
+ ndisc_send_ns(work->dev, NULL, &work->target, &mcaddr, NULL);
+ dev_put(work->dev);
+ kfree(w);
+}
+
static void rt6_probe(struct rt6_info *rt)
{
struct neighbour *neigh;
@@ -500,17 +518,23 @@ static void rt6_probe(struct rt6_info *r

if (!neigh ||
time_after(jiffies, neigh->updated + rt->rt6i_idev->cnf.rtr_probe_interval)) {
- struct in6_addr mcaddr;
- struct in6_addr *target;
+ struct __rt6_probe_work *work;

- if (neigh) {
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+
+ if (neigh && work)
neigh->updated = jiffies;
+
+ if (neigh)
write_unlock(&neigh->lock);
- }

- target = (struct in6_addr *)&rt->rt6i_gateway;
- addrconf_addr_solict_mult(target, &mcaddr);
- ndisc_send_ns(rt->dst.dev, NULL, target, &mcaddr, NULL);
+ if (work) {
+ INIT_WORK(&work->work, rt6_probe_deferred);
+ work->target = rt->rt6i_gateway;
+ dev_hold(rt->dst.dev);
+ work->dev = rt->dst.dev;
+ schedule_work(&work->work);
+ }
} else {
out:
write_unlock(&neigh->lock);