From 1a040eaca1a22f8da8285ceda6b5e4a2cb704867 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov 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 Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries") Acked-by: Herbert Xu Signed-off-by: David S. Miller --- 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 22fd0419b314..ff667e18b2d6 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); }