From 1a040eaca1a22f8da8285ceda6b5e4a2cb704867 Mon Sep 17 00:00:00 2001
From: Nikolay Aleksandrov <razor@blackwall.org>
Date: Tue, 9 Jun 2015 10:23:57 -0700
Subject: [PATCH] bridge: fix multicast router rlist endless loop
Since the addition of sysfs multicast router support if one set
multicast_router to "2" more than once, then the port would be added to
the hlist every time and could end up linking to itself and thus causing an
endless loop for rlist walkers.
So to reproduce just do:
echo 2 > multicast_router; echo 2 > multicast_router;
in a bridge port and let some igmp traffic flow, for me it hangs up
in br_multicast_flood().
Fix this by adding a check in br_multicast_add_router() if the port is
already linked.
The reason this didn't happen before the addition of multicast_router
sysfs entries is because there's a !hlist_unhashed check that prevents
it.
Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries")
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/bridge/br_multicast.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 22fd0419b3145..ff667e18b2d63 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1167,6 +1167,9 @@ static void br_multicast_add_router(struct net_bridge *br,
struct net_bridge_port *p;
struct hlist_node *slot = NULL;
+ if (!hlist_unhashed(&port->rlist))
+ return;
+
hlist_for_each_entry(p, &br->router_list, rlist) {
if ((unsigned long) port >= (unsigned long) p)
break;
@@ -1194,12 +1197,8 @@ static void br_multicast_mark_router(struct net_bridge *br,
if (port->multicast_router != 1)
return;
- if (!hlist_unhashed(&port->rlist))
- goto timer;
-
br_multicast_add_router(br, port);
-timer:
mod_timer(&port->multicast_router_timer,
now + br->multicast_querier_interval);
}
--
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