If a macvlan/macvtap creation fails in register_netdevice in
call_netdevice_notifiers(NETDEV_REGISTER) then while cleaning things up in
rollback_registered_many it invokes macvlan_uninit. This results in
port->count being decremented twice (in macvlan_uninit and in
macvlan_common_newlink).
A similar problem may exist in the ipvlan driver.
This patch adds priv_flags to struct macvlan_dev and a flag that
macvlan_uninit can use to determine if it is invoked in the context of a
failed newlink.
In macvtap_device_event(NETDEV_UNREGISTER) it also avoids cleaning up
/dev/tapNN in case creation of the char device had previously failed.
Tested in 3.18.
The failure can be reproduced by running the script below a few times. The
script creates macvtap interfaces in different namespaces causing along the
way sysfs_warn_dup failures in macvtap_device_event(NETDEV_REGISTER)
because of conflicting ifindexes, and finally a panic or
"unregister_netdevice: waiting for ddev to become free".
for ((ns=1; ns<3; ns++))
do
ip netns add ns${ns}
ip netns exec ns${ns} ip link add dev ddev type dummy
done
for ((ns=1; ns<3; ns++))
do
for ((mv=0; mv<2; mv++))
do
ret=1
while [ ${ret} != 0 ]
do
ip netns exec ns${ns} ip link add link ddev name \
macvtap${ns}${mv} type macvtap
ret=$?
done &
done
done
sleep 5
ls /dev/tap*
for ((ns=1; ns<3; ns++))
do
ip netns exec ns${ns} ip link del ddev &
done
sleep 2
ls /dev/tap*
for ((ns=1; ns<3; ns++))
do
ip netns del ns${ns}
done
Signed-off-by: Francesco Ruggeri <[email protected]>
---
drivers/net/macvlan.c | 11 ++++++++---
drivers/net/macvtap.c | 2 ++
include/linux/if_macvlan.h | 3 +++
3 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index 2bcf1f3..11065af 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -823,9 +823,12 @@ static void macvlan_uninit(struct net_device *dev)
free_percpu(vlan->pcpu_stats);
macvlan_flush_sources(port, vlan);
- port->count -= 1;
- if (!port->count)
- macvlan_port_destroy(port->dev);
+
+ if (!(vlan->priv_flags & MACVLAN_PRIV_FLAG_REGISTERING)) {
+ port->count -= 1;
+ if (!port->count)
+ macvlan_port_destroy(port->dev);
+ }
}
static struct rtnl_link_stats64 *macvlan_dev_get_stats64(struct net_device *dev,
@@ -1313,7 +1316,9 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
}
port->count += 1;
+ vlan->priv_flags |= MACVLAN_PRIV_FLAG_REGISTERING;
err = register_netdevice(dev);
+ vlan->priv_flags &= ~MACVLAN_PRIV_FLAG_REGISTERING;
if (err < 0)
goto destroy_port;
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 95394ed..e770221 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -1303,6 +1303,8 @@ static int macvtap_device_event(struct notifier_block *unused,
}
break;
case NETDEV_UNREGISTER:
+ if (vlan->minor == 0)
+ break;
devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
device_destroy(macvtap_class, devt);
macvtap_free_minor(vlan);
diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
index a4ccc31..7cf82d8 100644
--- a/include/linux/if_macvlan.h
+++ b/include/linux/if_macvlan.h
@@ -48,6 +48,7 @@ struct macvlan_dev {
netdev_features_t set_features;
enum macvlan_mode mode;
u16 flags;
+ u16 priv_flags;
/* This array tracks active taps. */
struct macvtap_queue __rcu *taps[MAX_MACVTAP_QUEUES];
/* This list tracks all taps (both enabled and disabled) */
@@ -63,6 +64,8 @@ struct macvlan_dev {
unsigned int macaddr_count;
};
+#define MACVLAN_PRIV_FLAG_REGISTERING 1
+
static inline void macvlan_count_rx(const struct macvlan_dev *vlan,
unsigned int len, bool success,
bool multicast)
--
1.8.1.4