Re: 24rc8: unregister_netdevice: waiting for ... to become free

From: David Miller
Date: Sun May 04 2008 - 00:11:27 EST


From: David Miller <davem@xxxxxxxxxxxxx>
Date: Fri, 02 May 2008 05:45:36 -0700 (PDT)

> From: "Roland" <devzero@xxxxxx>
> Date: Fri, 2 May 2008 14:38:36 +0200
>
> > it seems it`s lapbether driver
> >
> > reproduce:
> >
> > on system with pcnet32 (vmware) do
> >
> > modprobe pcnet32
> > modprobe lapbether
> > modprobe -r lapbether
> > modprobe -r pcnet32 -> hang -> unregister_netdevice: waiting for eth0 to
> > become free
>
> lapbeth_cleanup_driver() unregisters the netdevice, but does not
> release the reference to lapbeth->ethdev in those device instances.
>
> Once this happens, and the lapbeth_dev_notifier is unregistered,
> these references will leak forever.

Roland, does this fix your bug?

lapbeth: Release ->ethdev when unregistering device.

Otherwise it leaks forever.

Based upon a report by Roland <devzero@xxxxxx>

Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>

diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index b5860b9..24fd613 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -459,6 +459,7 @@ static void __exit lapbeth_cleanup_driver(void)
list_for_each_safe(entry, tmp, &lapbeth_devices) {
lapbeth = list_entry(entry, struct lapbethdev, node);

+ dev_put(lapbeth->ethdev);
unregister_netdevice(lapbeth->axdev);
}
rtnl_unlock();
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