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

[Ansis Atteka]

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?

>
> Thanks,
>
> Ben.
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