From: Thomas Gleixner <tglx@kernel.org>
To: "André Almeida" <andrealmeid@igalia.com>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>
Cc: linux-kernel@vger.kernel.org, Carlos O'Donell <carlos@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Florian Weimer <fweimer@redhat.com>,
Rich Felker <dalias@aerifal.cx>,
Torvald Riegel <triegel@redhat.com>,
Darren Hart <dvhart@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Arnd Bergmann <arnd@arndb.de>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>
Subject: Re: [RFC PATCH] futex: Introduce __vdso_robust_futex_unlock
Date: Thu, 12 Mar 2026 21:19:56 +0100 [thread overview]
Message-ID: <87ikb0pzpv.ffs@tglx> (raw)
In-Reply-To: <2993f778-c4f4-4aa8-8e42-1dca4d5e29e1@igalia.com>
On Thu, Mar 12 2026 at 10:46, André Almeida wrote:
> Em 11/03/2026 15:54, Mathieu Desnoyers escreveu:
> I would also have `uval` instead of `val = 0`, because even though the
> most common semanthics for futex is that (LOCK_FREE == 0), futex has no
> predetermined semanthics of what each value means, and the userspace is
> free to choose what value they want to choose for a free lock.
That's true for non-robust futexes, but robust futexes have clearly
defined semantics vs. the userspace value:
0: unlocked
!= 0: PID of the owner
So uval is useless as the unlock value can't be anything else than 0,
no?
Thanks,
tglx
next prev parent reply other threads:[~2026-03-12 20:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-11 18:54 [RFC PATCH] futex: Introduce __vdso_robust_futex_unlock Mathieu Desnoyers
2026-03-11 20:11 ` Mathieu Desnoyers
2026-03-12 8:49 ` Florian Weimer
2026-03-12 13:13 ` Mathieu Desnoyers
2026-03-12 14:12 ` Florian Weimer
2026-03-12 14:14 ` André Almeida
2026-03-12 16:09 ` Mathieu Desnoyers
2026-03-12 13:46 ` André Almeida
2026-03-12 14:04 ` Mathieu Desnoyers
2026-03-12 18:40 ` Mathieu Desnoyers
2026-03-12 18:58 ` André Almeida
2026-03-12 19:10 ` Thomas Gleixner
2026-03-12 19:16 ` Mathieu Desnoyers
2026-03-13 8:20 ` Florian Weimer
2026-03-12 20:19 ` Thomas Gleixner [this message]
2026-03-12 21:28 ` Mathieu Desnoyers
2026-03-12 22:23 ` Thomas Gleixner
2026-03-12 22:52 ` Mathieu Desnoyers
2026-03-13 12:12 ` Sebastian Andrzej Siewior
2026-03-13 12:17 ` Mathieu Desnoyers
2026-03-13 13:29 ` Sebastian Andrzej Siewior
2026-03-13 13:35 ` Mathieu Desnoyers
2026-03-16 17:12 ` Thomas Gleixner
2026-03-16 19:36 ` Mathieu Desnoyers
2026-03-16 20:27 ` Thomas Gleixner
2026-03-16 21:01 ` Mathieu Desnoyers
2026-03-16 22:19 ` Thomas Gleixner
2026-03-16 22:30 ` Mathieu Desnoyers
2026-03-16 23:29 ` Thomas Gleixner
2026-03-20 18:13 ` Mathieu Desnoyers
2026-03-24 21:35 ` Thomas Gleixner
2026-03-25 14:12 ` Mathieu Desnoyers
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