unregister_netdevice: waiting for eth0 to become free

unregister_netdevice: waiting for eth0 to become free

[roland]

hi list,

I have come across a problem on a SLES8 (2.4 kernel based) system today.

getting "unregister_netdevice: waiting for eth0 to become free" on shutdown 
and the shutdown got stuck at this point. needed to do a hard reset to 
continue.

by some search via google/vmware-forum i found a hint very soon (this was 
for RedHat, but also worked with SLES)

------------------------------------------------
In many Linux distributions, if IPv6 is enabled, VMware Tools cannot be 
configured with vmware-config-tools.pl after installation. In this case,
VMware Tools is unable to set the network device correctly for the virtual 
machine, and displays a message similar to
Unloading pcnet32 module
unregister_netdevice: waiting for eth0 to become free
This message repeats continuously until you reboot the virtual machine. To 
prevent this problem in virtual machines running Linux, disable IPv6 before 
installing VMware Tools.
To disable IPv6 in a virtual machine running Linux:
1 If the file /etc/sysconfig/network contains the line NETWORKING_IPV6=yes, 
change the line to NETWORKING_IPV6=no.

2 In the file /etc/modules.conf, add the following lines:
alias ipv6 off
alias net-pf-10 off

After you disable IPv6, you should be able to install and configure VMware 
Tools successfully.
------------------------------------------------

this solved my shutdown problem.  (network driver wasn`t pcnet32 but vmxnet 
, which is a vmware specific network device)

anyway - i wondered about this "waiting to become free".
this is just a workaround, not a solution.
what if i needed to use ipv6 ?

before i disabled ipv6 (as it is being recommended) , i tried some manual 
steps to disable ipv6, but failed.

don`t have the sles8 here at home, but trying to disable ipv6 "manually" on 
a newer system gives a similar error:

vserver1:~ # rmmod ipv6
ERROR: Module ipv6 is in use by ip6t_REJECT
vserver1:~ # rmmod ip6t_REJECT
ERROR: Module ip6t_REJECT is in use

ok - rmmod telling me, that ip6t_REJECT is in use.

but - what/who is using it ?

i disabled all network services for which lsof had shown that they had an 
ipv6 socket open, i also did "ifconfig sit0 down", which seems to be a ipv6 
related network device, but still having ip6t_REJECT in use.

now my questions:

- how  can i determine what "component" (i.e. one of userspace app, device, 
kernel-thread....whatever) is using a module, so i`m able to unload that 
module ?
- is there sort of "lsof" for kernel modules ?
- what is causing the unregister_netdevice to fail ? is it an older bug 
which has been resolved in later kernels ?

i`m quite sure, that i have seen this issue in the past, more then once and 
not related to vmware.
so, this is why i`m reporting it here and asking for help

regards
roland 

Re: unregister_netdevice: waiting for eth0 to become free

[YOSHIFUJI Hideaki / 吉藤英明]

In article <01a501c6ff74$6fc52c80$962e8d52@aldipc> (at Fri, 3 Nov 2006 19:18:17 +0100), "roland" <devzero@web.de> says:

> vserver1:~ # rmmod ipv6
> ERROR: Module ipv6 is in use by ip6t_REJECT
> vserver1:~ # rmmod ip6t_REJECT
> ERROR: Module ip6t_REJECT is in use

The ipv6 module cannot be unloaded once it has been
loaded.

I'm not sure what is happened with vmware.

--yoshfuji

Re: unregister_netdevice: waiting for eth0 to become free

[roland]

> The ipv6 module cannot be unloaded once it has been
> loaded.

sorry,  i thought i could rmmod evey module which was insmod/modprobe'd 
before and i didn`t know that there are exceptions

> I'm not sure what is happened with vmware.

i think this is not completely related to vmware - but maybe this is being 
triggered more often by vmware ?
http://www.google.de/search?hl=de&q=%22unregister_netdevice%3A+waiting+for+eth0+to+become+free

it`s really strange, but after taking a look,  vmware seems to recommend 
disabling ipv6 for _every_ linux based guest OS in general:
http://pubs.vmware.com/guestnotes/wwhelp/wwhimpl/common/html/wwhelp.htm?context=gos_ww5_output&file=choose_install_guest_os.html

since there are already running millions of  linux based VMs in this world, 
i think this isn`t very good "promotion" for ipv6, if vmware recommending 
disabling it.
ok, there are not that much people already needing ipv6 NOW, but the later 
they are running it and the later outstanding bugs being fixed, the harder 
it will be to convert from ipv4 to ipv6....

roland



----- Original Message ----- 
From: "YOSHIFUJI Hideaki / ????" <yoshfuji@linux-ipv6.org>
To: <devzero@web.de>
Cc: <linux-net@vger.kernel.org>; <linux-kernel@vger.kernel.org>; 
<yoshfuji@linux-ipv6.org>
Sent: Friday, November 03, 2006 7:47 PM
Subject: Re: unregister_netdevice: waiting for eth0 to become free


> In article <01a501c6ff74$6fc52c80$962e8d52@aldipc> (at Fri, 3 Nov 2006 
> 19:18:17 +0100), "roland" <devzero@web.de> says:
>
>> vserver1:~ # rmmod ipv6
>> ERROR: Module ipv6 is in use by ip6t_REJECT
>> vserver1:~ # rmmod ip6t_REJECT
>> ERROR: Module ip6t_REJECT is in use
>
> The ipv6 module cannot be unloaded once it has been
> loaded.
>
> I'm not sure what is happened with vmware.
>
> --yoshfuji 

Re: unregister_netdevice: waiting for eth0 to become free

[Stephen Hemminger]

On Fri, 3 Nov 2006 20:53:09 +0100
"roland" <devzero@web.de> wrote:

> > The ipv6 module cannot be unloaded once it has been
> > loaded.
> 
> sorry,  i thought i could rmmod evey module which was insmod/modprobe'd 
> before and i didn`t know that there are exceptions
> 
> > I'm not sure what is happened with vmware.
> 
> i think this is not completely related to vmware - but maybe this is being 
> triggered more often by vmware ?
> http://www.google.de/search?hl=de&q=%22unregister_netdevice%3A+waiting+for+eth0+to+become+free
> 
> it`s really strange, but after taking a look,  vmware seems to recommend 
> disabling ipv6 for _every_ linux based guest OS in general:
> http://pubs.vmware.com/guestnotes/wwhelp/wwhimpl/common/html/wwhelp.htm?context=gos_ww5_output&file=choose_install_guest_os.html
> 
> since there are already running millions of  linux based VMs in this world, 
> i think this isn`t very good "promotion" for ipv6, if vmware recommending 
> disabling it.
> ok, there are not that much people already needing ipv6 NOW, but the later 
> they are running it and the later outstanding bugs being fixed, the harder 
> it will be to convert from ipv4 to ipv6....
> 
> roland
> 
> 

Vmware has there own pseudo ethernet device and unless you have the source for it.
It would be hard to tell if it correctly manages itself.


-- 
Stephen Hemminger <shemminger@osdl.org>

Re: unregister_netdevice: waiting for eth0 to become free

[YOSHIFUJI Hideaki / 吉藤英明]

In article <01d001c6ff81$b4bb5dc0$962e8d52@aldipc> (at Fri, 3 Nov 2006 20:53:09 +0100), "roland" <devzero@web.de> says:

> > I'm not sure what is happened with vmware.
> 
> i think this is not completely related to vmware - but maybe this is being 
> triggered more often by vmware ?
> http://www.google.de/search?hl=de&q=%22unregister_netdevice%3A+waiting+for+eth0+to+become+free

I think all except for vmware related ones seem ancient
reports and I believe we have fixed them.

--yoshfuji

Re: unregister_netdevice: waiting for eth0 to become free

[devzero]

>Vmware has there own pseudo ethernet device and unless you have the source for it.
>It would be hard to tell if it correctly manages itself.

VMware is able to emulate three different network card types:

- AMD Am79C970A - PCnet LANCE PCI Ethernet Controller (linux pcnet32 driver)
- Intel E1000 (e1000 driver)
- VMXNET - VMware PCI Ethernet Adapter (vmxnet, vmware`s own driver)

so there are 3 different drivers being used inside the guest OS for networking virtual machines.

rumours tell, that the vmxnet driver is sort of a mess, but i have seen the unregister_netdevice problem with pcnet32 AND with vmxnet - and all of the vmware readme`s are telling:

"In many Linux distributions, if IPv6 is enabled, VMware Tools cannot be configured with vmware-config-tools.pl after installation. In this case, VMware Tools is unable to set the network device correctly for the virtual machine, and displays a message similar to
Unloading pcnet32 module
unregister_netdevice: waiting for eth0 to become free"

so - this is the native linux driver for pcnet32 which fails get unloaded _before_ the driver being replaced by the vmware specific one and the virtual nic being switched to the VMXNET adapter.....

anyway - i got that problem while shutting down a VM, not while installing vmware tools.

btw - just came across this posting from jesper juhl:
http://marc.theaimsgroup.com/?l=linux-kernel&m=115703768804826&w=2

roland




> -----Ursprüngliche Nachricht-----
> Von: Stephen Hemminger <shemminger@osdl.org>
> Gesendet: 03.11.06 20:57:54
> An: "roland" <devzero@web.de>
> CC: <yoshfuji@linux-ipv6.org>, <linux-net@vger.kernel.org>,   <linux-kernel@vger.kernel.org>
> Betreff: Re: unregister_netdevice: waiting for eth0 to become free


> On Fri, 3 Nov 2006 20:53:09 +0100
> "roland" <devzero@web.de> wrote:
> 
> > > The ipv6 module cannot be unloaded once it has been
> > > loaded.
> > 
> > sorry,  i thought i could rmmod evey module which was insmod/modprobe'd 
> > before and i didn`t know that there are exceptions
> > 
> > > I'm not sure what is happened with vmware.
> > 
> > i think this is not completely related to vmware - but maybe this is being 
> > triggered more often by vmware ?
> > http://www.google.de/search?hl=de&q=%22unregister_netdevice%3A+waiting+for+eth0+to+become+free
> > 
> > it`s really strange, but after taking a look,  vmware seems to recommend 
> > disabling ipv6 for _every_ linux based guest OS in general:
> > http://pubs.vmware.com/guestnotes/wwhelp/wwhimpl/common/html/wwhelp.htm?context=gos_ww5_output&file=choose_install_guest_os.html
> > 
> > since there are already running millions of  linux based VMs in this world, 
> > i think this isn`t very good "promotion" for ipv6, if vmware recommending 
> > disabling it.
> > ok, there are not that much people already needing ipv6 NOW, but the later 
> > they are running it and the later outstanding bugs being fixed, the harder 
> > it will be to convert from ipv4 to ipv6....
> > 
> > roland
> > 
> > 
> 
> Vmware has there own pseudo ethernet device and unless you have the source for it.
> It would be hard to tell if it correctly manages itself.
> 
> 
> -- 
> Stephen Hemminger <shemminger@osdl.org>


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Re: unregister_netdevice: waiting for eth0 to become free

[Stephen Hemminger]

On Fri, 03 Nov 2006 21:31:01 +0100
devzero@web.de wrote:

> >Vmware has there own pseudo ethernet device and unless you have the source for it.
> >It would be hard to tell if it correctly manages itself.
> 
> VMware is able to emulate three different network card types:
> 
> - AMD Am79C970A - PCnet LANCE PCI Ethernet Controller (linux pcnet32 driver)
> - Intel E1000 (e1000 driver)
> - VMXNET - VMware PCI Ethernet Adapter (vmxnet, vmware`s own driver)
> 
> so there are 3 different drivers being used inside the guest OS for networking virtual machines.
> 
> rumours tell, that the vmxnet driver is sort of a mess, but i have seen the unregister_netdevice problem with pcnet32 AND with vmxnet - and all of the vmware readme`s are telling:
> 
> "In many Linux distributions, if IPv6 is enabled, VMware Tools cannot be configured with vmware-config-tools.pl after installation. In this case, VMware Tools is unable to set the network device correctly for the virtual machine, and displays a message similar to
> Unloading pcnet32 module
> unregister_netdevice: waiting for eth0 to become free"
> 
> so - this is the native linux driver for pcnet32 which fails get unloaded _before_ the driver being replaced by the vmware specific one and the virtual nic being switched to the VMXNET adapter.....
> 
> anyway - i got that problem while shutting down a VM, not while installing vmware tools.
> 
> btw - just came across this posting from jesper juhl:
> http://marc.theaimsgroup.com/?l=linux-kernel&m=115703768804826&w=2
> 
> roland

You are also looking at 2.4 code which is OLD and probably broken in the
device ref counting. Lots of work went into cleaning up the shutdown and device
ref counting for 2.6, and I'm not surprised if 2.4 has problems.

Re: unregister_netdevice: waiting for eth0 to become free

[roland]

>You are also looking at 2.4 code which is OLD and probably broken in the
>device ref counting. Lots of work went into cleaning up the shutdown and 
>device
>ref counting for 2.6, and I'm not surprised if 2.4 has problems.

thanks. from what i found on different postings, it seems that this issue 
really has been adressed several times.
have seen it for 2.6 kernels though, vmware still recommending disabling 
ipv6 for suse 10.1 , but maybe this is just for "historical reason". 
furthermore jesper reported it for 2.6.18, but maybe that the problem now 
happens under very rare circumstances.
probably worth mentioning here, that two probably related bugs are in "not 
resolved" state at:
http://bugzilla.kernel.org/show_bug.cgi?id=6698 and 
http://bugzilla.kernel.org/show_bug.cgi?id=6197

i will keep an eye on our systems and report if i can see this on any more 
recent kernels.

thanks for your help!

roland

----- Original Message ----- 
From: "Stephen Hemminger" <shemminger@osdl.org>
To: <devzero@web.de>
Cc: <greearb@candelatech.com>; <jesper.juhl@gmail.com>; 
<linux-kernel@vger.kernel.org>; <linux-net@vger.kernel.org>; 
<yoshfuji@linux-ipv6.org>
Sent: Friday, November 03, 2006 10:04 PM
Subject: Re: unregister_netdevice: waiting for eth0 to become free


> On Fri, 03 Nov 2006 21:31:01 +0100
> devzero@web.de wrote:
>
>> >Vmware has there own pseudo ethernet device and unless you have the 
>> >source for it.
>> >It would be hard to tell if it correctly manages itself.
>>
>> VMware is able to emulate three different network card types:
>>
>> - AMD Am79C970A - PCnet LANCE PCI Ethernet Controller (linux pcnet32 
>> driver)
>> - Intel E1000 (e1000 driver)
>> - VMXNET - VMware PCI Ethernet Adapter (vmxnet, vmware`s own driver)
>>
>> so there are 3 different drivers being used inside the guest OS for 
>> networking virtual machines.
>>
>> rumours tell, that the vmxnet driver is sort of a mess, but i have seen 
>> the unregister_netdevice problem with pcnet32 AND with vmxnet - and all 
>> of the vmware readme`s are telling:
>>
>> "In many Linux distributions, if IPv6 is enabled, VMware Tools cannot be 
>> configured with vmware-config-tools.pl after installation. In this case, 
>> VMware Tools is unable to set the network device correctly for the 
>> virtual machine, and displays a message similar to
>> Unloading pcnet32 module
>> unregister_netdevice: waiting for eth0 to become free"
>>
>> so - this is the native linux driver for pcnet32 which fails get unloaded 
>> _before_ the driver being replaced by the vmware specific one and the 
>> virtual nic being switched to the VMXNET adapter.....
>>
>> anyway - i got that problem while shutting down a VM, not while 
>> installing vmware tools.
>>
>> btw - just came across this posting from jesper juhl:
>> http://marc.theaimsgroup.com/?l=linux-kernel&m=115703768804826&w=2
>>
>> roland
>
> You are also looking at 2.4 code which is OLD and probably broken in the
> device ref counting. Lots of work went into cleaning up the shutdown and 
> device
> ref counting for 2.6, and I'm not surprised if 2.4 has problems.