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From: Dmitry Osipenko <digetx@gmail.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
	Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
	Stephen Boyd <sboyd@kernel.org>
Cc: linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Rafael Wysocki <rjw@rjwysocki.net>,
	Sibi Sankar <sibis@codeaurora.org>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>
Subject: Re: [PATCH 07/13] opp: Allow _generic_set_opp_clk_only() to work for non-freq devices
Date: Thu, 21 Jan 2021 23:26:43 +0300	[thread overview]
Message-ID: <9b2638e6-b842-8737-e5a0-aeeb84927fce@gmail.com> (raw)
In-Reply-To: <1585f6c21ea8aee64fe4da0bf72b36ea4d74a779.1611227342.git.viresh.kumar@linaro.org>

21.01.2021 14:17, Viresh Kumar пишет:
> In order to avoid conditional statements at the caller site, this patch
> updates _generic_set_opp_clk_only() to work for devices that don't
> change frequency (like power domains, etc.). Return 0 if the clk pointer
> passed to this routine is not valid.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
...

Hello Viresh,

Thank you very much for yours effort! I gave a quick test to this series
and instantly found one small issue in this patch.

> +	/* We may reach here for devices which don't change frequency */
> +	if (unlikely(!clk))

I replaced dev_pm_opp_set_voltage() with dev_pm_opp_set_opp() in the
Tegra PD driver and got a crash, which happens because the above line
should be:

	if (IS_ERR(clk))

The opp_table->clk is initialized to ERR_PTR(-ENOENT) if device doesn't
have a clock, like a power domain device in my case.

Everything works good after fixing this patch. I'll keep testing and
will be taking a closer look at the rest of the patches over this weekend.

For the record, here is a backtrace of the crash:

Unable to handle kernel NULL pointer dereference at virtual address 00000016
...
(clk_set_rate) from (_set_opp)
(_set_opp) from (dev_pm_opp_set_opp)
(dev_pm_opp_set_opp) from (tegra_genpd_set_performance_state)
(tegra_genpd_set_performance_state) from (_genpd_set_performance_state)
(_genpd_set_performance_state) from (dev_pm_genpd_set_performance_state)
(dev_pm_genpd_set_performance_state) from (_set_required_opp)
(_set_required_opp) from (_set_opp)
(_set_opp) from (dev_pm_opp_set_rate)
(dev_pm_opp_set_rate) from (host1x_runtime_resume)
(host1x_runtime_resume) from (genpd_runtime_resume)
(genpd_runtime_resume) from (__rpm_callback)
(__rpm_callback) from (rpm_callback)
(rpm_callback) from (rpm_resume)
(rpm_resume) from (__pm_runtime_resume)
(__pm_runtime_resume) from (host1x_probe)
(host1x_probe) from (platform_probe)
(platform_probe) from (really_probe)
(really_probe) from (driver_probe_device)
(driver_probe_device) from (device_driver_attach)
(device_driver_attach) from (__driver_attach)
(__driver_attach) from (bus_for_each_dev)
(bus_for_each_dev) from (bus_add_driver)
(bus_add_driver) from (driver_register)
(driver_register) from (__platform_register_drivers)
(__platform_register_drivers) from (host1x_module_init)
(host1x_module_init) from (do_one_initcall)
(do_one_initcall) from (kernel_init_freeable)
(kernel_init_freeable) from (kernel_init)

WARNING: multiple messages have this Message-ID
From: Dmitry Osipenko <digetx@gmail.com>
To: Viresh Kumar <viresh.kumar@linaro.org>,
	Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
	Stephen Boyd <sboyd@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
	linux-pm@vger.kernel.org, Rafael Wysocki <rjw@rjwysocki.net>,
	linux-kernel@vger.kernel.org, Sibi Sankar <sibis@codeaurora.org>,
	"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 07/13] opp: Allow _generic_set_opp_clk_only() to work for non-freq devices
Date: Thu, 21 Jan 2021 23:26:43 +0300	[thread overview]
Message-ID: <9b2638e6-b842-8737-e5a0-aeeb84927fce@gmail.com> (raw)
In-Reply-To: <1585f6c21ea8aee64fe4da0bf72b36ea4d74a779.1611227342.git.viresh.kumar@linaro.org>

21.01.2021 14:17, Viresh Kumar пишет:
> In order to avoid conditional statements at the caller site, this patch
> updates _generic_set_opp_clk_only() to work for devices that don't
> change frequency (like power domains, etc.). Return 0 if the clk pointer
> passed to this routine is not valid.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
...

Hello Viresh,

Thank you very much for yours effort! I gave a quick test to this series
and instantly found one small issue in this patch.

> +	/* We may reach here for devices which don't change frequency */
> +	if (unlikely(!clk))

I replaced dev_pm_opp_set_voltage() with dev_pm_opp_set_opp() in the
Tegra PD driver and got a crash, which happens because the above line
should be:

	if (IS_ERR(clk))

The opp_table->clk is initialized to ERR_PTR(-ENOENT) if device doesn't
have a clock, like a power domain device in my case.

Everything works good after fixing this patch. I'll keep testing and
will be taking a closer look at the rest of the patches over this weekend.

For the record, here is a backtrace of the crash:

Unable to handle kernel NULL pointer dereference at virtual address 00000016
...
(clk_set_rate) from (_set_opp)
(_set_opp) from (dev_pm_opp_set_opp)
(dev_pm_opp_set_opp) from (tegra_genpd_set_performance_state)
(tegra_genpd_set_performance_state) from (_genpd_set_performance_state)
(_genpd_set_performance_state) from (dev_pm_genpd_set_performance_state)
(dev_pm_genpd_set_performance_state) from (_set_required_opp)
(_set_required_opp) from (_set_opp)
(_set_opp) from (dev_pm_opp_set_rate)
(dev_pm_opp_set_rate) from (host1x_runtime_resume)
(host1x_runtime_resume) from (genpd_runtime_resume)
(genpd_runtime_resume) from (__rpm_callback)
(__rpm_callback) from (rpm_callback)
(rpm_callback) from (rpm_resume)
(rpm_resume) from (__pm_runtime_resume)
(__pm_runtime_resume) from (host1x_probe)
(host1x_probe) from (platform_probe)
(platform_probe) from (really_probe)
(really_probe) from (driver_probe_device)
(driver_probe_device) from (device_driver_attach)
(device_driver_attach) from (__driver_attach)
(__driver_attach) from (bus_for_each_dev)
(bus_for_each_dev) from (bus_add_driver)
(bus_add_driver) from (driver_register)
(driver_register) from (__platform_register_drivers)
(__platform_register_drivers) from (host1x_module_init)
(host1x_module_init) from (do_one_initcall)
(do_one_initcall) from (kernel_init_freeable)
(kernel_init_freeable) from (kernel_init)

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  reply	other threads:[~2021-01-21 20:28 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21 11:17 [PATCH 00/13] opp: Implement dev_pm_opp_set_opp() Viresh Kumar
2021-01-21 11:17 ` Viresh Kumar
2021-01-21 11:17 ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 01/13] opp: Rename _opp_set_rate_zero() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 02/13] opp: No need to check clk for errors Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 03/13] opp: Keep track of currently programmed OPP Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 21:41   ` Dmitry Osipenko
2021-01-21 21:41     ` Dmitry Osipenko
2021-01-22  4:45     ` Viresh Kumar
2021-01-22  4:45       ` Viresh Kumar
2021-01-22 14:31       ` Dmitry Osipenko
2021-01-22 14:31         ` Dmitry Osipenko
2021-01-25  3:12         ` Viresh Kumar
2021-01-25  3:12           ` Viresh Kumar
2021-01-27 16:31       ` Akhil P Oommen
2021-01-28  4:14         ` Viresh Kumar
2021-01-28  4:14           ` Viresh Kumar
2021-07-07 10:24   ` Ionela Voinescu
2021-07-07 10:24     ` Ionela Voinescu
2021-07-08  7:53     ` Viresh Kumar
2021-07-08  7:53       ` Viresh Kumar
2021-07-09  8:57       ` Ionela Voinescu
2021-07-09  8:57         ` Ionela Voinescu
2021-07-12  4:14         ` Viresh Kumar
2021-07-12  4:14           ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 04/13] opp: Split _set_opp() out of dev_pm_opp_set_rate() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 05/13] opp: Allow _set_opp() to work for non-freq devices Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 06/13] opp: Allow _generic_set_opp_regulator() " Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 07/13] opp: Allow _generic_set_opp_clk_only() " Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 20:26   ` Dmitry Osipenko [this message]
2021-01-21 20:26     ` Dmitry Osipenko
2021-01-22  4:35     ` Viresh Kumar
2021-01-22  4:35       ` Viresh Kumar
2021-01-25 21:09       ` Dmitry Osipenko
2021-01-25 21:09         ` Dmitry Osipenko
2021-01-27  6:58         ` Viresh Kumar
2021-01-27  6:58           ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 08/13] opp: Update parameters of _set_opp_custom() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 09/13] opp: Implement dev_pm_opp_set_opp() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 10/13] cpufreq: qcom: Migrate to dev_pm_opp_set_opp() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 11/13] devfreq: tegra30: " Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 21:36   ` Dmitry Osipenko
2021-01-21 21:36     ` Dmitry Osipenko
2021-01-22  6:26     ` Viresh Kumar
2021-01-22  6:26       ` Viresh Kumar
2021-01-22 15:28       ` Dmitry Osipenko
2021-01-22 15:28         ` Dmitry Osipenko
2021-01-25  3:14         ` Viresh Kumar
2021-01-25  3:14           ` Viresh Kumar
2021-01-25 16:00           ` Dmitry Osipenko
2021-01-25 16:00             ` Dmitry Osipenko
2021-01-27  9:10   ` [PATCH V2 " Viresh Kumar
2021-01-27 10:02     ` Viresh Kumar
2021-01-27 15:58       ` Dmitry Osipenko
2021-01-28  7:01         ` Viresh Kumar
2021-02-01  0:21     ` Chanwoo Choi
2021-02-01 19:57     ` Dmitry Osipenko
2021-01-21 11:17 ` [PATCH 12/13] drm: msm: " Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar
2021-01-21 11:17 ` [PATCH 13/13] opp: Remove dev_pm_opp_set_bw() Viresh Kumar
2021-01-21 11:17   ` Viresh Kumar

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