| From | Ben Hutchings <> | Date | Sat, 10 Aug 2019 21:40:07 +0100 | Subject | [PATCH 3.16 079/157] net: bridge: multicast: use rcu to access port list from br_multicast_start_querier |
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3.16.72-rc1 review patch. If anyone has any objections, please let me know.
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From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
commit c5b493ce192bd7a4e7bd073b5685aad121eeef82 upstream.
br_multicast_start_querier() walks over the port list but it can be called from a timer with only multicast_lock held which doesn't protect the port list, so use RCU to walk over it.
Fixes: c83b8fab06fc ("bridge: Restart queries when last querier expires") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- net/bridge/br_multicast.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -2036,7 +2036,8 @@ static void br_multicast_start_querier(s __br_multicast_open(br, query); - list_for_each_entry(port, &br->port_list, list) { + rcu_read_lock(); + list_for_each_entry_rcu(port, &br->port_list, list) { if (port->state == BR_STATE_DISABLED || port->state == BR_STATE_BLOCKING) continue; @@ -2048,6 +2049,7 @@ static void br_multicast_start_querier(s br_multicast_enable(&port->ip6_own_query); #endif } + rcu_read_unlock(); } int br_multicast_toggle(struct net_bridge *br, unsigned long val)
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