From: Bart Van Assche <bvanassche@acm.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Zhiguo Niu <zhiguo.niu@unisoc.com>,
peterz@infradead.org, mingo@redhat.com, will@kernel.org,
longman@redhat.com, linux-kernel@vger.kernel.org,
niuzhiguo84@gmail.com, ke.wang@unisoc.com, xuewen.yan@unisoc.com,
Carlos Llamas <cmllamas@google.com>
Subject: Re: [PATCH V2] lockdep: fix deadlock issue between lockdep and rcu
Date: Thu, 1 Feb 2024 18:13:55 -0800 [thread overview]
Message-ID: <891016e2-0f3a-4617-bb8e-a2a3af0f78c8@acm.org> (raw)
In-Reply-To: <ZbwSxGpySa8RBt9A@boqun-archlinux>
On 2/1/24 13:53, Boqun Feng wrote:
> Have you checked the change in the patch? Now call_rcu_zapped() has been
> splitted into two parts: preparing the callback and calling call_rcu(),
> the preparing part checks and sets the delayed_free.scheduled under
> graph_lock(), so only one CPU/thread will win and do the actual
> call_rcu(). And the RCU callback free_zapped_rcu() will unset
> delayed_free.scheduled, again under graph_lock().
>
> If you think it's still possible, could you provide a case where the
> race may happen?
Yes, I noticed that call_rcu_zapped() has been split but the first time
I took a look at this patch I wasn't sure that the new code is correct.
After having taken a second look, the new mechanism for deciding whether
or not to invoke call_rcu() seems fine to me.
Bart.
next prev parent reply other threads:[~2024-02-02 2:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-17 7:48 Zhiguo Niu
2024-01-17 14:58 ` Waiman Long
2024-01-17 20:53 ` Boqun Feng
2024-02-01 16:35 ` Carlos Llamas
2024-02-01 17:22 ` Bart Van Assche
2024-02-01 19:58 ` Boqun Feng
2024-02-01 20:56 ` Bart Van Assche
2024-02-01 21:53 ` Boqun Feng
2024-02-02 2:13 ` Bart Van Assche [this message]
2024-02-02 8:19 ` Zhiguo Niu
2024-02-01 19:28 ` Bart Van Assche
2024-02-01 19:48 ` Boqun Feng
2024-02-01 21:24 ` Bart Van Assche
2024-02-01 21:55 ` Boqun Feng
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