Hi,
Sorry to butt in as an outsider, but this seems like a shockingly disrespectful discussion for such a wide CC list.
I don't want to make rules how you discuss things (I very rarely contribute), and I see the value in a frank discussion, but maybe you could continue with a reduced CC list?
I find it unlikely that I am the only one who could do without this.

Best regards,
Reimar Döffinger

On 5 Mar 2022, at 15:55, Byungchul Park [off-list ref] wrote:

On Fri, Mar 04, 2022 at 10:40:35PM -0500, Theodore Ts'o wrote:

quoted

On Fri, Mar 04, 2022 at 12:20:02PM +0900, Byungchul Park wrote:

quoted

I found a point that the two wait channels don't lead a deadlock in
some cases thanks to Jan Kara. I will fix it so that Dept won't
complain it.

I sent my last (admittedly cranky) message before you sent this.  I'm
glad you finally understood Jan's explanation.  I was trying to tell

Not finally. I've understood him whenever he tried to tell me something.

quoted

you the same thing, but apparently I failed to communicate in a

I don't think so. Your point and Jan's point are different. All he has
said make sense. But yours does not.

quoted

sufficiently clear manner.  In any case, what Jan described is a
fundamental part of how wait queues work, and I'm kind of amazed that
you were able to implement DEPT without understanding it.  (But maybe

Of course, it was possible because all that Dept has to know for basic
work is wait and event. The subtle things like what Jan told me help
Dept be better.

quoted

that is why some of the DEPT reports were completely incomprehensible

It's because you are blinded to blame at it without understanding how
Dept works at all. I will fix those that must be fixed. Don't worry.

quoted

to me; I couldn't interpret why in the world DEPT was saying there was
a problem.)

I can tell you if you really want to understand why. But I can't if you
are like this.

quoted

In any case, the thing I would ask is a little humility.  We regularly
use lockdep, and we run a huge number of stress tests, throughout each
development cycle.

Sure.

quoted

So if DEPT is issuing lots of reports about apparently circular
dependencies, please try to be open to the thought that the fault is

No one was convinced that Dept doesn't have a fault. I think your
worries are too much.

quoted

in DEPT, and don't try to argue with maintainers that their code MUST
be buggy --- but since you don't understand our code, and DEPT must be

No one argued that their code must be buggy, either. So I don't think
you have to worry about what's never happened.

quoted

theoretically perfect, that it is up to the Maintainers to prove to
you that their code is correct.

I am going to gently suggest that it is at least as likely, if not
more likely, that the failure is in DEPT or your understanding of what

No doubt. I already think so. But it doesn't mean that I have to keep
quiet without discussing to imporve Dept. I will keep improving Dept in
a reasonable way.

quoted

how kernel wait channels and locking works.  After all, why would it
be that we haven't found these problems via our other QA practices?

Let's talk more once you understand how Dept works at least 10%. Or I
think we cannot talk in a productive way.