Re: PROBLEM: 2.6.11-rc2 hangs on bridge shutdown (br0)

[Matthias-Christian Ott <matthias.christian@tiscali.de>]

Mirko Parthey wrote:

>My Debian machine hangs during shutdown, with messages like this:
>unregister_netdevice: waiting for br0 to become free. Usage count = 1
>
>I narrowed it down to the command
>  # brctl delbr br0
>which does not return in the circumstances shown below.
>
>The problem is reproducible with both 2.6.11-rc2 from kernel.org and the
>Debian kernel-image-2.6.10-1-686.
>
>My .config is taken from the above mentioned Debian kernel, adapted to
>2.6.11-rc2 and the processor type set to Pentium Classic. (I can email
>the .config on request).
>
>How to reproduce the problem (I tried this on a Pentium 4 machine):
>
>boot: linux init=/bin/bash
>[...booting...]
># mount proc -t proc /proc
># ifconfig lo 127.0.0.1
># brctl addbr br0
># modprobe e100           # also reproducible with 3c5x9
># brctl addif br0 eth0
># ifconfig br0 192.168.1.1
># ifconfig eth0 up
># ifconfig lo down
># lsmod | grep bridge
>bridge                 48888  0
># brctl delif br0 eth0
># ifconfig br0 down
># brctl delbr br0
>unregister_netdevice: waiting for br0 to become free. Usage count = 1
>unregister_netdevice: waiting for br0 to become free. Usage count = 1
>[...this message again and again, but no progress...]
>
>I'm also surprised that the reference count for the bridge module is
>zero, even when it is in use.
>
>Please let me know if you need any further information,
>and please Cc me on replies (I am not subscribed to linux-kernel).
>
>Thanks,
>Mirko
>-
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Hi!
I have a similar problem with my wlan modul, this patch should fix it (I 
disables the check function [untested]):

diff -Nru linux-2.6.11-rc2/net/core/dev.c 
linux-2.6.11-rc2-ott/net/core/dev.c
--- linux-2.6.11-rc2/net/core/dev.c    2005-01-26 22:27:31.000000000 +0100
+++ linux-2.6.11-rc2-ott/net/core/dev.c    2005-01-31 00:47:34.000000000 
+0100
@@ -2974,7 +2974,7 @@
             netdev_unregister_sysfs(dev);
             dev->reg_state = NETREG_UNREGISTERED;
 
-            netdev_wait_allrefs(dev);
+            //netdev_wait_allrefs(dev);
 
             /* paranoia */
             BUG_ON(atomic_read(&dev->refcnt));

Matthias-Christian Ott