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From: Thomas Gleixner <tglx@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>,
	Benjamin Segall <bsegall@google.com>,
	Eric Dumazet <edumazet@google.com>,
	Andrey Vagin <avagin@openvz.org>,
	Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Cyrill Gorcunov <gorcunov@gmail.com>
Subject: Re: [patch V3 17/18] posix-timers: Provide a mechanism to allocate a given timer ID
Date: Tue, 11 Mar 2025 23:05:34 +0100	[thread overview]
Message-ID: <87msdrz0i9.ffs@tglx> (raw)
In-Reply-To: <Z9CsstMf-EVZpsiH@pavilion.home>

On Tue, Mar 11 2025 at 22:35, Frederic Weisbecker wrote:
> Le Sat, Mar 08, 2025 at 05:48:47PM +0100, Thomas Gleixner a écrit :
>> @@ -364,6 +389,16 @@ static enum hrtimer_restart posix_timer_
>>  	return HRTIMER_NORESTART;
>>  }
>>  
>> +long posixtimer_create_prctl(unsigned long ctrl)
>> +{
>> +	if (ctrl > PR_TIMER_CREATE_RESTORE_IDS_ON)
>> +		return -EINVAL;
>> +
>> +	guard(spinlock_irq)(&current->sighand->siglock);
>> +	current->signal->timer_create_restore_ids = ctrl == PR_TIMER_CREATE_RESTORE_IDS_ON;
>
> Is the locking necessary here? It's not used on the read side.
> It only makes sense if more flags are to be added later in struct signal and the
> fields write can race.

True.

> Also do we want to carry this PR_TIMER_CREATE_RESTORE_IDS_ON accross exec? Posix
> timers are removed then anyway.

Indeed, we should clear that.

  reply	other threads:[~2025-03-11 22:05 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-08 16:48 [patch V3 00/18] posix-timers: Rework the global hash table and provide a sane mechanism for CRIU Thomas Gleixner
2025-03-08 16:48 ` [patch V3 01/18] posix-timers: Ensure that timer initialization is fully visible Thomas Gleixner
2025-03-08 21:39   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 02/18] posix-timers: Initialise timer before adding it to the hash table Thomas Gleixner
2025-03-11 13:25   ` Frederic Weisbecker
2025-03-11 14:16     ` Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Eric Dumazet
2025-03-08 16:48 ` [patch V3 03/18] posix-timers: Add cond_resched() to posix_timer_add() search loop Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Eric Dumazet
2025-03-08 16:48 ` [patch V3 04/18] posix-timers: Cleanup includes Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 05/18] posix-timers: Remove a few paranoid warnings Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 06/18] posix-timers: Remove SLAB_PANIC from kmem cache Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 07/18] posix-timers: Use guards in a few places Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 08/18] posix-timers: Simplify lock/unlock_timer() Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 09/18] posix-timers: Rework timer removal Thomas Gleixner
2025-03-09 23:17   ` Frederic Weisbecker
2025-03-10  6:33     ` Thomas Gleixner
2025-03-10  8:13   ` [patch V3a " Thomas Gleixner
2025-03-13 11:31     ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 10/18] posix-timers: Make lock_timer() use guard() Thomas Gleixner
2025-03-10 11:57   ` Frederic Weisbecker
2025-03-10 17:36     ` Thomas Gleixner
2025-03-10 22:16       ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Peter Zijlstra
2025-03-08 16:48 ` [patch V3 11/18] posix-timers: Make signal_struct:: Next_posix_timer_id an atomic_t Thomas Gleixner
2025-03-10 22:57   ` Frederic Weisbecker
2025-03-11 13:41   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Eric Dumazet
2025-03-08 16:48 ` [patch V3 12/18] posix-timers: Improve hash table performance Thomas Gleixner
2025-03-11 13:44   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 13/18] posix-timers: Switch to jhash32() Thomas Gleixner
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 14/18] posix-timers: Avoid false cacheline sharing Thomas Gleixner
2025-03-11 13:53   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-13 22:13   ` [patch V3 14/18] " David Laight
2025-03-17  6:20   ` Nysal Jan K.A.
2025-03-08 16:48 ` [patch V3 15/18] posix-timers: Make per process list RCU safe Thomas Gleixner
2025-03-11 15:29   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 16/18] posix-timers: Dont iterate /proc/$PID/timers with sighand:: Siglock held Thomas Gleixner
2025-03-08 22:38   ` Cyrill Gorcunov
2025-03-11 15:26   ` Frederic Weisbecker
2025-03-13 11:31   ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-08 16:48 ` [patch V3 17/18] posix-timers: Provide a mechanism to allocate a given timer ID Thomas Gleixner
2025-03-08 22:25   ` Cyrill Gorcunov
2025-03-11 21:35   ` Frederic Weisbecker
2025-03-11 22:05     ` Thomas Gleixner [this message]
2025-03-11 22:07       ` [patch V3a " Thomas Gleixner
2025-03-11 22:32         ` Frederic Weisbecker
2025-03-12  7:56           ` Cyrill Gorcunov
2025-03-12 11:24             ` Thomas Gleixner
2025-03-12 11:31               ` Thomas Gleixner
2025-03-12 12:41               ` Cyrill Gorcunov
2025-03-12 17:45                 ` Thomas Gleixner
2025-03-13 11:31         ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2025-03-12 12:59     ` [patch V3 17/18] " Cyrill Gorcunov
2025-03-08 16:48 ` [patch V3 18/18] selftests/timers/posix-timers: Add a test for exact allocation mode Thomas Gleixner
2025-03-10  8:11   ` [patch V3a " Thomas Gleixner
2025-03-11 21:44     ` Frederic Weisbecker
2025-03-13 11:31     ` [tip: timers/core] " tip-bot2 for Thomas Gleixner

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