Re: How to unload lksctp kernel module?

[Vlad Yasevich <vyasevich@gmail.com>]

On 02/26/2013 10:00 AM, Jon Leighton wrote:
> On 2/26/13 9:13 AM, Vlad Yasevich wrote:
>> On 02/25/2013 05:00 PM, Daniel Borkmann wrote:
>>> (cc: linux-sctp, which is the right list to address this question)
>>>
>>> On 02/25/2013 03:39 PM, Jon Leighton wrote:
>>>> I'm trying to unload the lksctp kernel module (sudo modprobe -r sctp),
>>>> but the operation fails with "FATAL: Module sctp is in use.". lsmod
>>>> shows a reference count of 2 for sctp. If I restart the machine, and
>>>> load the lksctp module by running a simple SCTP based program, the
>>>> module loads, but the reference count is 2 again, and the module can't
>>>> be unloaded. I've also tried to force the unload with sudo rmmod -f
>>>> sctp, but that fails with "ERROR: Removing 'sctp': Resource temporarily
>>>> unavailable". Is there a way to unload the module? I'm running Ubuntu
>>>> 10.04 LTS with linux kernel 2.6.32-45-generic-pae. Thanks for any help.
>>
>> rmmod -f used to work, but I haven't tried it lately.
>>
>> The reason for the ref=2 is that when lksctp starts up, it creates a
>> control socket which holds those 2 refs on the module. 'modprobe -r'
>> will not let you unload when the module is refed.  rmmod -f works
>> around that.
>
> sudo rmmod -f sctp returns "ERROR: Removing 'sctp': Resource temporarily
> unavailable". Is there any workaround for this? Or perhaps this means
> that I need to rebuild my kernel with CONFIG_MODULE_FORCE_UNLOAD enabled?

Yes, you need CONFIG_MODULE_FORCE_UNLOAD.  Without it rmmod -f doesn't work.

-vlad

>
>> -vlad
>>
>>>>
>>>> - Jon
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>