From: Hangbin Liu liuhangbin@gmail.com
[ Upstream commit 60380488e4e0b95e9e82aa68aa9705baa86de84c ]
Rafał found an issue that for non-Ethernet interface, if we down and up frequently, the memory will be consumed slowly.
The reason is we add allnodes/allrouters addressed in multicast list in ipv6_add_dev(). When link down, we call ipv6_mc_down(), store all multicast addresses via mld_add_delrec(). But when link up, we don't call ipv6_mc_up() for non-Ethernet interface to remove the addresses. This makes idev->mc_tomb getting bigger and bigger. The call stack looks like:
addrconf_notify(NETDEV_REGISTER) ipv6_add_dev ipv6_dev_mc_inc(ff01::1) ipv6_dev_mc_inc(ff02::1) ipv6_dev_mc_inc(ff02::2)
addrconf_notify(NETDEV_UP) addrconf_dev_config /* Alas, we support only Ethernet autoconfiguration. */ return;
addrconf_notify(NETDEV_DOWN) addrconf_ifdown ipv6_mc_down igmp6_group_dropped(ff02::2) mld_add_delrec(ff02::2) igmp6_group_dropped(ff02::1) igmp6_group_dropped(ff01::1)
After investigating, I can't found a rule to disable multicast on non-Ethernet interface. In RFC2460, the link could be Ethernet, PPP, ATM, tunnels, etc. In IPv4, it doesn't check the dev type when calls ip_mc_up() in inetdev_event(). Even for IPv6, we don't check the dev type and call ipv6_add_dev(), ipv6_dev_mc_inc() after register device.
So I think it's OK to fix this memory consumer by calling ipv6_mc_up() for non-Ethernet interface.
v2: Also check IFF_MULTICAST flag to make sure the interface supports multicast
Reported-by: Rafał Miłecki zajec5@gmail.com Tested-by: Rafał Miłecki zajec5@gmail.com Fixes: 74235a25c673 ("[IPV6] addrconf: Fix IPv6 on tuntap tunnels") Fixes: 1666d49e1d41 ("mld: do not remove mld souce list info when set link down") Signed-off-by: Hangbin Liu liuhangbin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/addrconf.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3189,6 +3189,10 @@ static void addrconf_dev_config(struct n (dev->type != ARPHRD_6LOWPAN) && (dev->type != ARPHRD_NONE)) { /* Alas, we support only Ethernet autoconfiguration. */ + idev = __in6_dev_get(dev); + if (!IS_ERR_OR_NULL(idev) && dev->flags & IFF_UP && + dev->flags & IFF_MULTICAST) + ipv6_mc_up(idev); return; }