[ovs-dev] [PATCH ] debian: place kernel module to satisfy depmod search.

[Saurabh Mohan]

On 10/14/2015 04:58 PM, Ansis Atteka wrote:
> On Wed, Oct 14, 2015 at 4:08 PM, Ben Pfaff <blp at nicira.com> wrote:
>> On Wed, Oct 14, 2015 at 03:28:24PM -0700, Joe Stringer wrote:
>>> On 14 October 2015 at 15:21, Ben Pfaff <blp at nicira.com> wrote:
>>>> On Tue, Oct 06, 2015 at 04:35:32PM -0700, Saurabh Mohan wrote:
>>>>> On Ubuntu depmod's search priority is configured in /etc/depmod to be
>>>>> updates and then the kernel built-in directory.
>>>>> $ cat /etc/depmod.d/ubuntu.conf
>>>>> search updates ubuntu built-in
>>>>>
>>>>> Thus change the placement of openvswitch.ko under updates/ not kernel/updates.
>>>>>
>>>>> Signed-off-by: Saurabh Mohan <saurabh at cplanenetworks.com>
>>>>
>>>> This appears to be correct, but I'm confused about how this could have
>>>> not been noticed for years.  Did something change recently?
>>>
>>> We recently changed it from kernel/ to kernel/updates (prior to v2.4
>>> release), and the commit message suggests it was previously
>>> nondeterministic:
>>>
>>> commit b519432205c36bda5c7331f77a49eaaa919967ad
>>> Author: Ansis Atteka <aatteka at nicira.com>
>>> Date:   Tue May 26 16:49:49 2015 -0700
>>>
>>>      debian: install openvswitch kernel module under "updates" directory
>>>
>>>      This patch fixes a bug where "modprobe openvswitch" command on Ubuntu
>>>      distribution would have sometimes tried to load OVS kernel module that
>>>      shipped together with Linux Kernel, even though one had also installed
>>>      OVS datapath debian package created with module-assistant.  Because of
>>>      this issue force-reload-kmod command occasionally malfunctioned and
>>>      failed to load the right kernel module.
>>>
>>>      This bug happened *occasionally* because the default Ubuntu depmod
>>>      configuration in /etc/depmod.d/ubuntu.conf is set to look for kernel
>>>      modules first in "updates" directory, then in "ubuntu" directory and
>>>      then in other directories.  If there were two openvswitch.ko modules
>>>      in "other directories", then modprobe would have loaded kernel
>>>      module that was nondeterministically listed first by file system.
>>
>> OK, I understand why it was nondeterministic before, but where does
>> kernel/updates come in then, since it seems to be different from and not
>> as high-priority as "updates"?  Does anyone know?
>
> I am still trying to find the answer in my email history why I ended
> up using "kernel/updates" over "updates".
>
> Saurabh, did you encounter an issue where the wrong kernel module was
> loaded or is this to achieve conformance?
(resending it again as previously i did not include everyone. Sorry)

Ansis, we tried using this patch but still noticed that the wrong kernel 
module was getting selected. The only way to fix it was
to put the module outside kernel/ directory.
>
>>
>> Thanks,
>>
>> Ben.
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