Re: USB Attached SCSI breakage due no udev involvement

[Dio Putra]

On 5/10/20 2:32 PM, Greg KH wrote:
> On Sun, May 10, 2020 at 02:10:04PM +0700, Dio Putra wrote:
>> On 5/10/20 1:54 PM, Greg KH wrote:
>>> On Sun, May 10, 2020 at 01:48:24PM +0700, Dio Putra wrote:
>>>> On 5/10/20 12:47 PM, Greg KH wrote:
>>>>> On Sun, May 10, 2020 at 09:55:57AM +0700, Dio Putra wrote:
>>>>>> Hi, it's first time for me to report user-space breakage in here, so
>>>>>> i'm begging your pardon.
>>>>>>
>>>>>> I want to report that Linux 5.4 breaking my USB mount workflow due
>>>>>> udevadm monitor report here (I'm using vanilla kernel 5.4.39 on
>>>>>> Slackware64 Current and vanilla kernel 4.4.221 on Slackware64 14.2):
>>>>>
>>>>> <snip>
>>>>>
>>>>> Sorry, but what actually changed that you can see in the logs?
>>>> Sorry, what do you mean? The dmesg log or the kernel changelogs?
>>>
>>> Either, your message made them pretty impossible to compare with all of
>>> the line-wrapping :(
>>>
>> I'm so sorry for first message mess, because that message has been sent by
>> Gmail Website. Can I send my logs as attachment? I try to convenient everyone
>> here. ( FYI, I just switched to Thunderbird with these settings:
>> https://www.kernel.org/doc/html/v4.12/process/email-clients.html#thunderbird-gui ) 
> 
> Sure, attachments work, but better yet, if you can show the difference
> in a few lines that is much nicer than having to dig through large
> numbers of log files.
> 
Okay, I'll attach long messages and trim it as far as I can.

>>>>> What functionality broke?  What used to work that no longer does work?
>>>>>
>>>> Yes, it supposed that just work and kernel could talk with udev, not just handled by the kernel.
>>>
>>> I don't understand, what functionality changed?  What exactly used to
>>> work that no longer does?
>> linux-5.4 has been never called the udev dependencies whereas
>> linux-4.4 will call any udev dependencies if necessary, that's the problem.
> 
> I do not understand what exactly you mean by "call udev dependencies".
> 
> udev is used to create symlinks and set user/group permissions on device
> nodes in /dev/ which is created by devtmpfs.  What exactly is not
> happening in your /dev/ with the move to a newer kernel?
> 
Would I send my dmesg log with "udev.log-priority=debug" as attachment then?

>>> Did you change anything else other than the kernel on your system?  Did
>>> you change to a newer version of udev/systemd or anything else?
>>>
>> I'm using eudev-master from their official mirror github:
>> https://github.com/gentoo/eudev
> 
> Have you contacted the eudev developers to see if something different
> needs to be set in your kernel when moving 4 years in kernel development
> forward?  Are you sure you have all the correct config options enabled?
> 
It's my bad not to contact the eudev developers first. However I'm not quite
sure to contact the eudev developers would solve the problem, but CMIIW.

> Why such a huge leap forward all at once, how about going from 4.4.y to
> 4.9.y and then 4.14.y and then 5.4.y?  That might help narrow things
> down a bit easier.
> 
Unfortunately I need to think twice due almost ran out of electricity
here every time I power on my laptop for long time. So maybe I can't.

But if these steps are necessary, I'll think solution later.
> thanks,
> 
> greg k-h
>