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Subject: Re: [PATCH 2/8] kernel: unmask SIGSTOP for IO threads
From:   Stefan Metzmacher <metze@samba.org>
To:     Jens Axboe <axboe@kernel.dk>, Oleg Nesterov <oleg@redhat.com>
Cc:     io-uring@vger.kernel.org, torvalds@linux-foundation.org,
        ebiederm@xmission.com, linux-kernel@vger.kernel.org
References: <20210326003928.978750-1-axboe@kernel.dk>
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 <a179ad33-5656-b644-0d92-e74a6bd26cc8@kernel.dk>
 <8f2a4b48-77c9-393f-5194-100ed63c05fc@samba.org>
 <58f67a8b-166e-f19c-ccac-157153e4f17c@kernel.dk>
 <c61fc5eb-c997-738b-1a60-5e3db2754f49@samba.org>
Message-ID: <a891f9b7-81fb-5534-891c-306593961156@samba.org>
Date:   Thu, 1 Apr 2021 16:53:12 +0200
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Hi Jens,

>>> I don't assume signals wanted by userspace should potentially handled in an io_thread...
>>> e.g. things set with fcntl(fd, F_SETSIG,) used together with F_SETLEASE?
>>
>> I guess we do actually need it, if we're not fiddling with
>> wants_signal() for them. To quell Oleg's concerns, we can just move it
>> to post dup_task_struct(), that should eliminate any race concerns
>> there.
> 
> If that one is racy, don' we better also want this one?
> https://lore.kernel.org/io-uring/438b738c1e4827a7fdfe43087da88bbe17eedc72.1616197787.git.metze@samba.org/T/#u
> 
> And clear tsk->pf_io_worker ?

As the workers don't clone other workers I guess it's fine to defer this to 5.13.

metze