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From: Lukasz Majewski <l.majewski@samsung.com>
To: Eduardo Valentin <edubezval@gmail.com>, Zhang Rui <rui.zhang@intel.com>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	Linux PM list <linux-pm@vger.kernel.org>,
	Vincenzo Frascino <vincenzo.frascino@st.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Lukasz Majewski <l.majewski@majess.pl>,
	Nobuhiro Iwamatsu <iwamatsu@nigauri.org>,
	Mikko Perttunen <mperttunen@nvidia.com>,
	Stephen Warren <swarren@wwwdotorg.org>,
	Thierry Reding <thierry.reding@gmail.com>,
	Alexandre Courbot <gnurou@gmail.com>,
	linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
	Lukasz Majewski <l.majewski@samsung.com>
Subject: [PATCH 7/8] thermal:core:fix: Initialize the max_state variable to 0
Date: Thu, 13 Nov 2014 18:02:44 +0100	[thread overview]
Message-ID: <1415898165-27406-8-git-send-email-l.majewski@samsung.com> (raw)
In-Reply-To: <1415898165-27406-1-git-send-email-l.majewski@samsung.com>

Pointer to the uninitialized max_state variable is passed to get the
maximal cooling state.
For CPU cooling device (cpu_cooling.c) the cpufreq_get_max_state() is
called, which even when error occurs will return the max_state variable
unchanged.
Since error for ->get_max_state() is not checked, the automatically
allocated value of max_state is used for (upper > max_state) comparison.
For any possible max_state value it is very unlikely that it will be less
than upper.
As a consequence, the cooling device is bind even without the backed
cpufreq table initialized.

This initialization will prevent from accidental binding trip points to
cpu freq cooling frequencies when cpufreq driver itself is not yet fully
initialized.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
---
 drivers/thermal/thermal_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 43b9070..413daa4 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -927,7 +927,7 @@ int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
 	struct thermal_instance *pos;
 	struct thermal_zone_device *pos1;
 	struct thermal_cooling_device *pos2;
-	unsigned long max_state;
+	unsigned long max_state = 0;
 	int result;
 
 	if (trip >= tz->trips || (trip < 0 && trip != THERMAL_TRIPS_NONE))
-- 
2.0.0.rc2

  parent reply	other threads:[~2014-11-13 17:02 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-24  8:27 [PATCH 0/3] thermal: fix: Various fixes for thermal subsystem Lukasz Majewski
2014-09-24  8:27 ` [PATCH 1/3] thermal: step_wise: fix: Prevent from binary overflow when trend is dropping Lukasz Majewski
2014-10-02 21:13   ` Eduardo Valentin
2014-10-03  7:26     ` Lukasz Majewski
2014-10-09  3:14   ` Zhang Rui
2014-09-24  8:27 ` [PATCH 2/3] thermal: core: fix: Initialize the max_state variable to 0 Lukasz Majewski
2014-10-02 22:26   ` Eduardo Valentin
2014-10-03  8:26     ` Lukasz Majewski
2014-10-06 18:01       ` Eduardo Valentin
2014-09-24  8:27 ` [PATCH 3/3] thermal: core: fix: Check return code of the ->get_max_state() callback Lukasz Majewski
2014-10-02 22:24   ` Eduardo Valentin
2014-10-03 10:40     ` Lukasz Majewski
2014-10-09  3:15       ` Zhang Rui
2014-10-09 16:47         ` Lukasz Majewski
2014-10-02 14:40 ` [PATCH 0/3] thermal: fix: Various fixes for thermal subsystem Lukasz Majewski
     [not found] ` <1411547232-21493-1-git-send-email-l.majewski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-11-13 17:02   ` [PATCH 0/8] thermal:cpu cooling:fix: Provide thermal core fixes with deferred probe for several drivers Lukasz Majewski
2014-11-13 17:02     ` Lukasz Majewski
2014-11-13 17:02     ` [PATCH 1/8] thermal:cpu cooling:armada: Provide deferred probing for armada driver Lukasz Majewski
2014-11-13 17:02     ` [PATCH 2/8] thermal:cpu cooling:kirkwood: Provide deferred probing for kirkwood driver Lukasz Majewski
2014-11-13 17:02     ` [PATCH 3/8] thermal:cpu cooling:rcar: Provide deferred probing for rcar driver Lukasz Majewski
2014-11-13 17:02     ` [PATCH 4/8] thermal:cpu cooling:spear: Provide deferred probing for spear driver Lukasz Majewski
2014-11-13 17:02     ` [PATCH 5/8] thermal:cpu cooling:tegra: Provide deferred probing for tegra driver Lukasz Majewski
2014-11-14 10:47       ` Mikko Perttunen
2014-11-14 11:24         ` Lukasz Majewski
2014-11-17 11:57           ` Thierry Reding
2014-11-17 12:51             ` Lukasz Majewski
2014-11-17 13:18               ` Thierry Reding
     [not found]         ` <5465DDC5.6090301-/1wQRMveznE@public.gmane.org>
2014-11-17 11:43           ` Thierry Reding
2014-11-17 11:43             ` Thierry Reding
2014-11-17 11:50             ` Lukasz Majewski
2014-11-17 12:01               ` Thierry Reding
2014-11-17 12:01                 ` Thierry Reding
2014-11-17 13:02                 ` Lukasz Majewski
2014-11-17 13:02                   ` Lukasz Majewski
2014-11-17 12:51             ` Mikko Perttunen
2014-11-17 12:51               ` Mikko Perttunen
2014-11-17 13:08               ` Thierry Reding
2014-11-17 13:24                 ` Mikko Perttunen
     [not found]       ` <1415898165-27406-6-git-send-email-l.majewski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-11-17 11:40         ` Thierry Reding
2014-11-17 11:40           ` Thierry Reding
2014-11-13 17:02     ` [PATCH 6/8] thermal:cpu cooling:ti: Provide deferred probing for ti drivers Lukasz Majewski
2014-11-20 19:00       ` Eduardo Valentin
2014-11-13 17:02     ` Lukasz Majewski [this message]
2014-11-18 10:16     ` [PATCH v2] thermal:core:fix: Check return code of the ->get_max_state() callback Lukasz Majewski
     [not found]       ` <1416305790-27746-1-git-send-email-l.majewski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-11-21 18:08         ` Eduardo Valentin
2014-11-21 18:08           ` Eduardo Valentin
2014-11-24 10:38           ` Lukasz Majewski
2014-11-24 11:00             ` Viresh Kumar
2014-11-24 11:00               ` Viresh Kumar
2014-11-24 14:24               ` Lukasz Majewski
2014-11-25 10:46                 ` Viresh Kumar
2014-11-24 18:02             ` Eduardo Valentin
2014-11-24 18:02               ` Eduardo Valentin
2014-11-24 20:28               ` Lukasz Majewski
     [not found]     ` <1415898165-27406-1-git-send-email-l.majewski-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>
2014-11-13 17:02       ` [PATCH 8/8] " Lukasz Majewski
2014-11-13 17:02         ` Lukasz Majewski
2014-11-20 18:54       ` [PATCH 0/8] thermal:cpu cooling:fix: Provide thermal core fixes with deferred probe for several drivers Eduardo Valentin
2014-11-20 18:54         ` Eduardo Valentin
2014-11-21  8:33         ` Lukasz Majewski
2014-11-21  2:47           ` Eduardo Valentin
2014-11-21 16:28             ` Lukasz Majewski
2014-11-21 16:28               ` Lukasz Majewski

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