Re: "Khelp module "ertt" can't unload until its refcount drops from 1 to 0." after "All buffers synced."?

On 11/19/21 4:29 AM, tuexen@freebsd.org wrote:
>> On 19. Nov 2021, at 00:11, Mark Millard <marklmi@yahoo.com> wrote:
>>
>>> On 2021-Nov-18, at 12:31, tuexen@freebsd.org <tuexen@FreeBSD.org> wrote:
>>>
>>>> On 17. Nov 2021, at 21:13, Mark Millard via freebsd-current <freebsd-current@freebsd.org> wrote:
>>>>
>>>> I've not noticed the ertt message before in:
>>>>
>>>> . . .
>>>> Waiting (max 60 seconds) for system thread `bufspacedaemon-1' to stop... done
>>>> All buffers synced.
>>>> Uptime: 1d9h57m18s
>>>> Khelp module "ertt" can't unload until its refcount drops from 1 to 0.
>>> Hi Mark,
>>>
>>> what kernel configuration are you using? What kernel modules are loaded?
>>
>> The shutdown was of my ZFS boot media but the machine is
>> currently doing builds on the UFS media. (The ZFS media is
>> present but not mounted). For now I provide information
>> from the booted UFS system. The UFS context is intended
>> to be nearly a copy of the brctl selection for main [so: 14]
>> from the ZFS media. Both systems have been doing the same
>> poudriere builds for various comparison/contrast purposes.
>> The current build activity will likely take 16+ hrs.
> Hi Mark,
> 
> thanks a lot for the information. I was contemplating whether this message
> was related to a recent change in the TCP congestion module handling, but
> since it was already there in February, this is not the case. Will try to
> reproduce this, but wasn't able up to now.

The congestion control changes just probably exacerbated the bug by
adding a new reference on this module, just as they exposed the bug
with khelp using the wrong SYSINIT subsystem.

-- 
John Baldwin