linux-kernel - Re: [PATCH 2/2] signal: don't allow STOP on PF_IO

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Message-ID: <20210322161529.GB20390@redhat.com>
Date:   Mon, 22 Mar 2021 17:15:29 +0100
From:   Oleg Nesterov <oleg@...hat.com>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     io-uring@...r.kernel.org, torvalds@...ux-foundation.org,
        ebiederm@...ssion.com, linux-kernel@...r.kernel.org,
        Stefan Metzmacher <metze@...ba.org>
Subject: Re: [PATCH 2/2] signal: don't allow STOP on PF_IO_WORKER threads

On 03/20, Jens Axboe wrote:
>
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -2349,6 +2349,10 @@ static bool do_signal_stop(int signr)
>
>  		t = current;
>  		while_each_thread(current, t) {
> +			/* don't STOP PF_IO_WORKER threads */
> +			if (t->flags & PF_IO_WORKER)
> +				continue;
> +

This is not enough. At least task_join_group_stop() should check
PF_IO_WORKER too.

Oleg.