From: Alan Stern <stern@rowland.harvard.edu>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Hernan Ponce de Leon <hernan.poncedeleon@huaweicloud.com>,
Arjan van de Ven <arjan@linux.intel.com>,
peterz@infradead.org, mingo@redhat.com, will@kernel.org,
longman@redhat.com, boqun.feng@gmail.com, akpm@osdl.org,
tglx@linutronix.de, joel@joelfernandes.org,
diogo.behrens@huawei.com, jonas.oberhauser@huawei.com,
linux-kernel@vger.kernel.org,
Hernan Ponce de Leon <hernanl.leon@huawei.com>,
stable@vger.kernel.org
Subject: Re: [PATCH] Fix data race in mark_rt_mutex_waiters
Date: Mon, 23 Jan 2023 12:34:37 -0500 [thread overview]
Message-ID: <Y87FLV0dWSyQz3NZ@rowland.harvard.edu> (raw)
In-Reply-To: <20230123164014.GN2948950@paulmck-ThinkPad-P17-Gen-1>
On Mon, Jan 23, 2023 at 08:40:14AM -0800, Paul E. McKenney wrote:
> In the case, the value read is passed into cmpxchg_relaxed(), which
> checks the value against memory. In this case, as Arjan noted, the only
> compiler-and-silicon difference between data_race() and READ_ONCE()
> is that use of data_race() might allow the compiler to do things like
> tear the load, thus forcing the occasional spurious cmpxchg_relaxed()
> failure.
Is it possible in theory for a torn load to cause a spurious
cmpxchg_relaxed() success? Or would that not matter here?
Alan
next prev parent reply other threads:[~2023-01-23 17:36 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-20 13:55 Hernan Ponce de Leon
2023-01-20 14:58 ` Arjan van de Ven
2023-01-20 15:54 ` Paul E. McKenney
2023-01-22 15:24 ` Hernan Ponce de Leon
2023-01-23 16:40 ` Paul E. McKenney
2023-01-23 17:34 ` Alan Stern [this message]
2023-01-23 17:48 ` Paul E. McKenney
2023-01-23 20:02 ` Jonas Oberhauser
2023-01-24 14:57 ` Hernan Ponce de Leon
2023-01-24 15:42 ` Waiman Long
2023-01-24 15:52 ` Peter Zijlstra
2023-01-24 16:04 ` Waiman Long
2023-01-26 9:42 ` Hernan Ponce de Leon
2023-01-26 12:20 ` Peter Zijlstra
2023-01-26 14:20 ` Peter Zijlstra
2023-01-26 21:07 ` Hernan Ponce de Leon
2023-01-26 22:10 ` David Laight
2023-01-27 1:46 ` Waiman Long
2023-03-01 16:32 ` lock_torture results for different patches: Antonio Paolillo
2023-03-06 7:58 ` Hernan Ponce de Leon
2023-03-10 17:11 ` Paul E. McKenney
2023-01-24 16:12 ` [PATCH] Fix data race in mark_rt_mutex_waiters Paul E. McKenney
2023-01-20 16:23 ` Peter Zijlstra
2023-01-20 16:58 ` David Laight
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