linux-kernel - Re: [6.5-rc5 regression] core dump hangs (was Re: [Bug report] fstests generic/051 (on xfs) hang on latest linux v6.5-rc5+)

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Message-ID: <ff34a007-fdd0-8575-8482-919ead39fc88@kernel.dk>
Date:   Mon, 12 Jun 2023 11:29:25 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     "Darrick J. Wong" <djwong@...nel.org>,
        Dave Chinner <david@...morbit.com>,
        Zorro Lang <zlang@...hat.com>, linux-xfs@...r.kernel.org,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Mike Christie <michael.christie@...cle.com>,
        "Michael S. Tsirkin" <mst@...hat.com>, linux-kernel@...r.kernel.org
Subject: Re: [6.5-rc5 regression] core dump hangs (was Re: [Bug report]
 fstests generic/051 (on xfs) hang on latest linux v6.5-rc5+)

On 6/12/23 10:57 AM, Linus Torvalds wrote:
> On Mon, Jun 12, 2023 at 9:45 AM Jens Axboe <axboe@...nel.dk> wrote:
>>
>> You snipped the suspicion in my reply on why that exists, to avoid
>> io_wq_worker_sleeping() triggering.
> 
> I'm not seeing why triggering io_wq_worker_sleeping() should even be a
> problem in the first place.
> 
> I suspect that is entirely historical too, and has to do with how it
> used to do that
> 
>         struct io_worker *worker = kthread_data(tsk);
>         struct io_wqe *wqe = worker->wqe;
> 
> back in the bad old days of kthreads.
> 
> But yeah, I don't know that code.

Looks fine to me to just kill it indeed, whatever we did need this
for is definitely no longer the case. I _think_ we used to have
something in the worker exit that would potentially sleep which
is why we killed it before doing that, now it just looks like dead
code.

-- 
Jens Axboe