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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Jiri Slaby <jirislaby@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, boqun.feng@gmail.com, bristot@redhat.com,
	bsegall@google.com, dietmar.eggemann@arm.com, jstultz@google.com,
	juri.lelli@redhat.com, longman@redhat.com, mgorman@suse.de,
	mingo@redhat.com, rostedt@goodmis.org, swood@redhat.com,
	vincent.guittot@linaro.org, vschneid@redhat.com, will@kernel.org
Subject: Re: [PATCH] futex: Avoid reusing outdated pi_state.
Message-ID: <20240116144632.cDj3SolO@linutronix.de>
References: <20240116130810.ji1YCxpg@linutronix.de>
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In-Reply-To: <20240116130810.ji1YCxpg@linutronix.de>

On 2024-01-16 14:08:12 [+0100], To Jiri Slaby wrote:
> --- a/kernel/futex/requeue.c
> +++ b/kernel/futex/requeue.c
> @@ -873,7 +873,7 @@ int futex_wait_requeue_pi(u32 __user *uaddr, unsigned=
 int flags,
>  		if (res)
>  			ret =3D (res < 0) ? res : 0;
> =20
> -		futex_unqueue_pi(&q);
> +		futex_unqueue_pi(&q, true);

This obviously needs the same change as futex_lock_pi() unless it is
okay to avoid the argument and remove it if it hasn't been removed. I
forgot that the requeue path has also signals & timeouts and so is
subject to the same problem.

Assuming we go that direction=E2=80=A6

>  		spin_unlock(q.lock_ptr);
> =20
>  		if (ret =3D=3D -EINTR) {

Sebastian