Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 27 Jun 2022 16:54:54 +0200
From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     linux-kernel@vger.kernel.org, mingo@redhat.com,
        ebiederm@xmission.com,
        Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <toke@redhat.com>,
        Kalle Valo <kvalo@kernel.org>,
        Johannes Berg <johannes@sipsolutions.net>
Subject: Re: [PATCH] signal: break out of wait loops on kthread_stop()
Message-ID: <YrnEvjcG8tmF3dRV@zx2c4.com>
References: <20220627120020.608117-1-Jason@zx2c4.com>
 <YrmwJyueoz1Z4ti0@hirez.programming.kicks-ass.net>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <YrmwJyueoz1Z4ti0@hirez.programming.kicks-ass.net>
Precedence: bulk

On Mon, Jun 27, 2022 at 03:27:03PM +0200, Peter Zijlstra wrote:
> On Mon, Jun 27, 2022 at 02:00:20PM +0200, Jason A. Donenfeld wrote:
> 
> > +bool __kthread_should_stop(struct task_struct *k)
> > +{
> > +	return (k->flags & PF_KTHREAD) &&
> > +	       test_bit(KTHREAD_SHOULD_STOP, &to_kthread(k)->flags);
> > +}
> 
> This used to be a racy pattern; not sure it still is since Eric poked at
> this last, but please use __to_kthread() instead.

Ah, indeed. Will send a v2.

Jason