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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Subject: Re: [PATCH] futex: Avoid reusing outdated pi_state.
Date: Tue, 16 Jan 2024 15:46:32 +0100	[thread overview]
Message-ID: <20240116144632.cDj3SolO@linutronix.de> (raw)
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 = (res < 0) ? res : 0;
>  
> -		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…

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

Sebastian

  parent reply	other threads:[~2024-01-16 14:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-16 13:08 [PATCH] futex: Avoid reusing outdated pi_state Sebastian Andrzej Siewior
2024-01-16 13:58 ` Jiri Slaby
2024-01-16 14:46 ` Sebastian Andrzej Siewior [this message]
2024-01-17 18:37 ` Thomas Gleixner
2024-01-18 11:54   ` [PATCH v2] " Sebastian Andrzej Siewior
2024-01-19 12:06     ` [tip: locking/urgent] futex: Prevent the reuse of stale pi_state tip-bot2 for Sebastian Andrzej Siewior

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