| Message ID | 1448983868-811-1-git-send-email-andrew@lunn.ch |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Andrew Lunn <andrew@lunn.ch> Date: Tue, 1 Dec 2015 16:31:08 +0100 > When a multicast group is joined on a socket, a struct ip_mc_socklist > is appended to the sockets mc_list containing information about the > joined group. > > If the interface is hot unplugged, this entry becomes stale. Prior to > commit 52ad353a5344f ("igmp: fix the problem when mc leave group") it > was possible to remove the stale entry by performing a > IP_DROP_MEMBERSHIP, passing either the old ifindex or ip address on > the interface. However, this fix enforces that the interface must > still exist. Thus with time, the number of stale entries grows, until > sysctl_igmp_max_memberships is reached and then it is not possible to > join and more groups. > > The previous patch fixes an issue where a IP_DROP_MEMBERSHIP is > performed without specifying the interface, either by ifindex or ip > address. However here we do supply one of these. So loosen the > restriction on device existence to only apply when the interface has > not been specified. This then restores the ability to clean up the > stale entries. > > Signed-off-by: Andrew Lunn <andrew@lunn.ch> > Fixes: 52ad353a5344f "(igmp: fix the problem when mc leave group") Applied and queued up for -stable, thanks Andrew. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index 6baf36e11808..05e4cba14162 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -2126,7 +2126,7 @@ int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr) ASSERT_RTNL(); in_dev = ip_mc_find_dev(net, imr); - if (!in_dev) { + if (!imr->imr_ifindex && !imr->imr_address.s_addr && !in_dev) { ret = -ENODEV; goto out; } @@ -2147,7 +2147,8 @@ int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr) *imlp = iml->next_rcu; - ip_mc_dec_group(in_dev, group); + if (in_dev) + ip_mc_dec_group(in_dev, group); /* decrease mem now to avoid the memleak warning */ atomic_sub(sizeof(*iml), &sk->sk_omem_alloc);
When a multicast group is joined on a socket, a struct ip_mc_socklist is appended to the sockets mc_list containing information about the joined group. If the interface is hot unplugged, this entry becomes stale. Prior to commit 52ad353a5344f ("igmp: fix the problem when mc leave group") it was possible to remove the stale entry by performing a IP_DROP_MEMBERSHIP, passing either the old ifindex or ip address on the interface. However, this fix enforces that the interface must still exist. Thus with time, the number of stale entries grows, until sysctl_igmp_max_memberships is reached and then it is not possible to join and more groups. The previous patch fixes an issue where a IP_DROP_MEMBERSHIP is performed without specifying the interface, either by ifindex or ip address. However here we do supply one of these. So loosen the restriction on device existence to only apply when the interface has not been specified. This then restores the ability to clean up the stale entries. Signed-off-by: Andrew Lunn <andrew@lunn.ch> Fixes: 52ad353a5344f "(igmp: fix the problem when mc leave group") --- v2: Don't dereference in_dev when it is NULL when calling ip_mc_dec_group(). Calling ip_mc_leave_src() is safe with a NULL in_dev. --- net/ipv4/igmp.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)