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From: Viresh Kumar <viresh.kumar@linaro.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	"Rafael J. Wysocki" <rafael@kernel.org>
Subject: Re: [PATCH 1/4] base/drivers/arch_topology: Remove useless check
Date: Tue, 30 Oct 2018 14:03:08 +0530	[thread overview]
Message-ID: <20181030083308.5znognajpwjvdxfv@vireshk-i7> (raw)
In-Reply-To: <d689e382-e4f2-0b03-03a5-2ff4a6bb88bb@linaro.org>

On 30-10-18, 08:55, Daniel Lezcano wrote:
> The workqueue is called from init_cpu_capacity_callback(). This one is
> called in the notifier callback. IOW the notification callback
> unregisters itself. But if it is not registered, it won't unregister,
> hence it won't call the workqueue and init_cpu_capacity_notifier() is
> not called.

Sorry, couldn't understand most of your reply :)

Though let me try to explain the problem I was trying to show you..

cpufreq-notifier-callback
        -> init_cpu_capacity_callback()
                -> free raw capacity
                -> queue_work() to unregister the notifier
                -> return

        ->init_cpu_capacity_callback() called again before work was processed.
                -> If we don't check raw_capacity, we may end up using
                NULL pointer, as the notifier isn't unregistered yet.

-- 
viresh

  reply	other threads:[~2018-10-30  8:33 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-29 16:23 [PATCH 1/4] base/drivers/arch_topology: Remove useless check Daniel Lezcano
2018-10-29 16:23 ` [PATCH 2/4] base/drivers/arch_topology: Replace mutex with READ_ONCE / WRITE_ONCE Daniel Lezcano
2018-10-30  5:57   ` Viresh Kumar
2018-11-23 13:58   ` Sudeep Holla
2018-11-23 16:04     ` Daniel Lezcano
2018-11-23 16:20       ` Sudeep Holla
2018-11-23 16:54         ` Daniel Lezcano
2018-11-26  8:27           ` Juri Lelli
2018-11-26  8:39             ` Daniel Lezcano
2018-11-26 11:33             ` Mark Brown
2018-10-29 16:23 ` [PATCH 3/4] base/drivers/topology: Move instructions in the error path Daniel Lezcano
2018-10-30  6:12   ` Viresh Kumar
2018-10-30  8:32     ` Daniel Lezcano
2018-10-29 16:23 ` [PATCH 4/4] base/drivers/topology: Default dmpis-mhz if they are not set in DT Daniel Lezcano
2018-10-30  7:13   ` Viresh Kumar
2018-10-30  8:39     ` Daniel Lezcano
2018-10-30  8:45       ` Viresh Kumar
2018-10-30  8:58   ` Viresh Kumar
2018-11-21 22:12     ` Daniel Lezcano
2018-11-22  4:29       ` Viresh Kumar
2018-11-22 10:29         ` Daniel Lezcano
2018-11-22 10:31           ` Viresh Kumar
2018-11-22 10:32             ` Daniel Lezcano
2018-11-22 11:11             ` Daniel Lezcano
2018-10-30  5:50 ` [PATCH 1/4] base/drivers/arch_topology: Remove useless check Viresh Kumar
2018-10-30  7:55   ` Daniel Lezcano
2018-10-30  8:33     ` Viresh Kumar [this message]
2018-10-30 13:35       ` Daniel Lezcano
2018-10-31  4:27         ` Viresh Kumar

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