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net: ipv6: Release route when device is unregistering

PATCH In review David Ahern 3 participants 3 messages Jun 7, 2017 – Jun 8, 2017

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Networking Network drivers IPv4/IPv6
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David Ahern

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#0 lore raw

PATCH 1/1 net: ipv6: Release route when device is unregistering

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 a1a22c12060e4 ("net: ipv6: Keep nexthop of multipath route on admin down")
Reported-by Roopa Prabhu <[email protected]>
Signed-off-by David Ahern <[email protected]>
---
 include/linux/netdevice.h | 5 +++++
 net/ipv6/route.c          | 1 +
 2 files changed, 6 insertions(+)
include/linux/netdevice.h +5 -0
index 3f39d27decf4..c06d93cfd719 100644
@@ -4261,6 +4261,11 @@ 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) {
net/ipv6/route.c +1 -0
index dc61b0b5e64e..7cebd954d5bb 100644
@@ -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;
Signature · 1 line
2.11.0 (Apple Git-81)
Acked-by on v1 1/1
#1 lore raw
Quoted 16 lines · David Ahern

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

Quoted 8 lines

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 a1a22c12060e4 ("net: ipv6: Keep nexthop of multipath route on admin down")
Reported-by Roopa Prabhu <[email protected]>
Signed-off-by David Ahern <[email protected]>

---

Acked-by Roopa Prabhu <[email protected]>

This patch fixes the issue for me. Thanks David.

maintainer
#2 lore raw
In reply to David Ahern

From: David Ahern <[email protected]>
Date: Wed, 7 Jun 2017 12:26:23 -0600

Quoted 16 lines

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

Quoted 7 lines

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 a1a22c12060e4 ("net: ipv6: Keep nexthop of multipath route on admin down")
Reported-by Roopa Prabhu <[email protected]>
Signed-off-by David Ahern <[email protected]>

Applied and queued up for -stable, thanks David.