[PATCH 3.4 093/107] ipv6: probe routes asynchronous in rt6_probe

lizf
2016-03-16T08:18:14Z

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

3.4.111-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit c2f17e827b419918c856131f592df9521e1a38e3 upstream.

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>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
net/ipv6/route.c | 37 +++++++++++++++++++++++++++++++------
1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 23b3304..c909217 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -404,6 +404,24 @@ 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;
@@ -422,15 +440,22 @@ static void rt6_probe(struct rt6_info *rt)
read_lock_bh(&neigh->lock);
if (!(neigh->nud_state & NUD_VALID) &&
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;
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+
+ if (work)
+ neigh->updated = jiffies;

- neigh->updated = jiffies;
read_unlock_bh(&neigh->lock);

- target = (struct in6_addr *)&neigh->primary_key;
- 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 {
read_unlock_bh(&neigh->lock);
}
--
1.9.1