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Subject: Re: [PATCH 0/6] Allow signals for IO threads
From:   Jens Axboe <axboe@kernel.dk>
To:     Stefan Metzmacher <metze@samba.org>, io-uring@vger.kernel.org
Cc:     torvalds@linux-foundation.org, ebiederm@xmission.com,
        oleg@redhat.com, linux-kernel@vger.kernel.org
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Date:   Fri, 26 Mar 2021 08:38:25 -0600
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On 3/26/21 7:59 AM, Jens Axboe wrote:
> On 3/26/21 7:54 AM, Jens Axboe wrote:
>>> The KILL after STOP deadlock still exists.
>>
>> In which tree? Sounds like you're still on the old one with that
>> incremental you sent, which wasn't complete.
>>
>>> Does io_wq_manager() exits without cleaning up on SIGKILL?
>>
>> No, it should kill up in all cases. I'll try your stop + kill, I just
>> tested both of them separately and didn't observe anything. I also ran
>> your io_uring-cp example (and found a bug in the example, fixed and
>> pushed), fwiw.
> 
> I can reproduce this one! I'll take a closer look.

OK, that one is actually pretty straight forward - we rely on cleaning
up on exit, but for fatal cases, get_signal() will call do_exit() for us
and never return. So we might need a special case in there to deal with
that, or some other way of ensuring that fatal signal gets processed
correctly for IO threads.

-- 
Jens Axboe