| From | Willy Tarreau <> | Subject | [PATCH 3.10 109/139] ipv6: avoid unregistering inet6_dev for loopback | Date | Wed, 1 Nov 2017 22:26:34 +0100 |
| |
From: WANG Cong <xiyou.wangcong@gmail.com>
commit 60abc0be96e00ca71bac083215ac91ad2e575096 upstream.
The per netns loopback_dev->ip6_ptr is unregistered and set to NULL when its mtu is set to smaller than IPV6_MIN_MTU, this leads to that we could set rt->rt6i_idev NULL after a rt6_uncached_list_flush_dev() and then crash after another call.
In this case we should just bring its inet6_dev down, rather than unregistering it, at least prior to commit 176c39af29bc ("netns: fix addrconf_ifdown kernel panic") we always override the case for loopback.
Thanks a lot to Andrey for finding a reliable reproducer.
Fixes: 176c39af29bc ("netns: fix addrconf_ifdown kernel panic") Reported-by: Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Daniel Lezcano <dlezcano@fr.ibm.com> Cc: David Ahern <dsahern@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: David Ahern <dsahern@gmail.com> Tested-by: Andrey Konovalov <andreyknvl@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu> --- net/ipv6/addrconf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index 9c4aa2e..5ea5f77 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2892,6 +2892,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, { struct net_device *dev = (struct net_device *) data; struct inet6_dev *idev = __in6_dev_get(dev); + struct net *net = dev_net(dev); int run_pending = 0; int err; @@ -2988,7 +2989,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, * IPV6_MIN_MTU stop IPv6 on this interface. */ if (dev->mtu < IPV6_MIN_MTU) - addrconf_ifdown(dev, 1); + addrconf_ifdown(dev, dev != net->loopback_dev); } break; -- 2.8.0.rc2.1.gbe9624a
|