Patchwork [net] ipv6: probe routes asynchronous in rt6_probe

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Submitter Hannes Frederic Sowa
Date Oct. 21, 2013, 4:17 a.m.
Message ID <20131021041715.GH27787@order.stressinduktion.org>
Download mbox | patch
Permalink /patch/285111/
State Accepted
Delegated to: David Miller
Headers show

Comments

Hannes Frederic Sowa - Oct. 21, 2013, 4:17 a.m.
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>
---
 net/ipv6/route.c | 38 +++++++++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 7 deletions(-)
David Miller - Oct. 21, 2013, 10:57 p.m.
From: Hannes Frederic Sowa <hannes@stressinduktion.org>
Date: Mon, 21 Oct 2013 06:17:15 +0200

> 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>

Looks good, applied and queued up for -stable, thanks Hannes.
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Patch

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index c3130ff..38c9418 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -476,6 +476,24 @@  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;
@@ -499,17 +517,23 @@  static void rt6_probe(struct rt6_info *rt)
 
 	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;
+
+		work = kmalloc(sizeof(*work), GFP_ATOMIC);
 
-		if (neigh) {
+		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);