Re: 2.6.7-rc3: unregister_netdevice: waiting for tun0 to become free. Usage count = 1

[Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>]

On Sun, Jun 13, 2004 at 09:07:25PM -0700, David S. Miller wrote:
> 
> Not written yet, but it will be of the form:
> 
>       idev = rt->idev;
>       SNMP_BUMP_BLAH_BLAH_STAT(idev);

OK, in that case either they all need to check whether idev is
NULL before doing this or we'll need to fix ->ifdown to set the
dev to something other than NULL.

BTW in looking at this I've found two bugs in the dst code wrt
cleaning up net devices.

1. The code in dst_dev_event relies on the entries with dev in it
getting onto the garbage list before it is called.  Unfortunately
for routing entries, the flushing is done asynchronusly so it is
entirely possible for the entries to get onto the garbage list after
dst_dev_event has been called twice (DOWN and then UNREGISTER).

This is not fatal though since another GC run will pick them up in
at most two minutes.  But the user may well be alarmed by those
dreaded "waiting for..." errors.

2. dst_dev_event doesn't clean up dst->child at all.

Cheers,
-- 
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Email:  Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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