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centosplus patch [bug#12711]
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commit 751eb6b6042a596b0080967c1a529a9fe98dac1d
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Author: Wei Yongjun <weiyongjun1@huawei.com>
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Date: Mon Sep 5 16:06:31 2016 +0800
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ipv6: addrconf: fix dev refcont leak when DAD failed
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In general, when DAD detected IPv6 duplicate address, ifp->state
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will be set to INET6_IFADDR_STATE_ERRDAD and DAD is stopped by a
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delayed work, the call tree should be like this:
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ndisc_recv_ns
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-> addrconf_dad_failure <- missing ifp put
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-> addrconf_mod_dad_work
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-> schedule addrconf_dad_work()
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-> addrconf_dad_stop() <- missing ifp hold before call it
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addrconf_dad_failure() called with ifp refcont holding but not put.
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addrconf_dad_work() call addrconf_dad_stop() without extra holding
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refcount. This will not cause any issue normally.
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But the race between addrconf_dad_failure() and addrconf_dad_work()
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may cause ifp refcount leak and netdevice can not be unregister,
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dmesg show the following messages:
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IPv6: eth0: IPv6 duplicate address fe80::XX:XXXX:XXXX:XX detected!
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...
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unregister_netdevice: waiting for eth0 to become free. Usage count = 1
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Cc: stable@vger.kernel.org
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Fixes: c15b1ccadb32 ("ipv6: move DAD and addrconf_verify processing
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to workqueue")
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Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Submitted-by: alfredo
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Applied-by: Akemi Yagi <toracat@centos.org>
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diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
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index b7d5ce6..dc65579 100644
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--- a/net/ipv6/addrconf.c
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+++ b/net/ipv6/addrconf.c
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@@ -1656,6 +1656,7 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp)
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spin_unlock_bh(&ifp->state_lock);
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addrconf_mod_dad_work(ifp, 0);
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+ in6_ifa_put(ifp);
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}
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/* Join to solicited addr multicast group.
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@@ -3300,6 +3301,7 @@ static void addrconf_dad_work(struct work_struct *w)
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addrconf_dad_begin(ifp);
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goto out;
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} else if (action == DAD_ABORT) {
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+ in6_ifa_hold(ifp);
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addrconf_dad_stop(ifp, 1);
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goto out;
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}
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