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net: ipv6: Release route when device is unregistering

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Roopa reported attempts to delete a bond device that is referenced in a
multipath route is hanging:

$ ifdown bond2    # ifupdown2 command that deletes virtual devices
unregister_netdevice: waiting for bond2 to become free. Usage count = 2

Steps to reproduce:
    echo 1 > /proc/sys/net/ipv6/conf/all/ignore_routes_with_linkdown
    ip link add dev bond12 type bond
    ip link add dev bond13 type bond
    ip addr add 2001:db8:2::0/64 dev bond12
    ip addr add 2001:db8:3::0/64 dev bond13
    ip route add 2001:db8:33::0/64 nexthop via 2001:db8:2::2 nexthop via 2001:db8:3::2
    ip link del dev bond12
    ip link del dev bond13

The root cause is the recent change to keep routes on a linkdown. Update
the check to detect when the device is unregistering and release the
route for that case.

Fixes: a1a22c1206 ("net: ipv6: Keep nexthop of multipath route on admin down")
Reported-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2017-06-07 12:26:23 -06:00 committed by David S. Miller
parent 0eed9cf584
commit 8397ed36b7
2 changed files with 6 additions and 0 deletions
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5
include/linux/netdevice.h
View File

@ -4262,6 +4262,11 @@ static inline const char *netdev_name(const struct net_device *dev)
return dev->name;
}
static inline bool netdev_unregistering(const struct net_device *dev)
{
return dev->reg_state == NETREG_UNREGISTERING;
}
static inline const char *netdev_reg_state(const struct net_device *dev)
{
switch (dev->reg_state) {

1
net/ipv6/route.c
View File

@ -2804,6 +2804,7 @@ static int fib6_ifdown(struct rt6_info *rt, void *arg)
if ((rt->dst.dev == dev || !dev) &&
rt != adn->net->ipv6.ip6_null_entry &&
(rt->rt6i_nsiblings == 0 ||
(dev && netdev_unregistering(dev)) ||
!rt->rt6i_idev->cnf.ignore_routes_with_linkdown))
return -1;