[PATCH] thermal: fix frequency table lookup bugs

From: Andrew Bresticker
Date: Mon Apr 08 2013 - 19:54:59 EST


The loops which are used to perform lookups in CPU frequency tables in
cpu_cooling and the Exynos thermal driver do not update the loop counter
if they encounter an invalid table entry, leading to an infinite loop in
that case.

Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
---
drivers/thermal/cpu_cooling.c | 19 ++++++++++---------
drivers/thermal/exynos_thermal.c | 8 ++++----
2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 836828e..e6db441 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -124,14 +124,14 @@ static int is_cpufreq_valid(int cpu)
static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
{
int ret = 0, i = 0;
- unsigned long level_index;
+ unsigned long level_index = 0;
bool descend = false;
struct cpufreq_frequency_table *table =
cpufreq_frequency_get_table(cpu);
if (!table)
return ret;

- while (table[i].frequency != CPUFREQ_TABLE_END) {
+ for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
continue;

@@ -143,24 +143,25 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
}

/*return if level matched and table in descending order*/
- if (descend && i == level)
+ if (descend && level_index == level)
return table[i].frequency;
- i++;
+ level_index++;
}
i--;
+ level_index--;

- if (level > i || descend)
+ if (level > level_index || descend)
return ret;
- level_index = i - level;
+ level = level_index - level;

/*Scan the table in reverse order and match the level*/
- while (i >= 0) {
+ for (; i >= 0; i--) {
if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
continue;
/*return if level matched*/
- if (i == level_index)
+ if (level_index == level)
return table[i].frequency;
- i--;
+ level_index--;
}
return ret;
}
diff --git a/drivers/thermal/exynos_thermal.c b/drivers/thermal/exynos_thermal.c
index d5e6267..524b2a0 100644
--- a/drivers/thermal/exynos_thermal.c
+++ b/drivers/thermal/exynos_thermal.c
@@ -237,7 +237,7 @@ static int exynos_get_crit_temp(struct thermal_zone_device *thermal,

static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq)
{
- int i = 0, ret = -EINVAL;
+ int i, level = 0, ret = -EINVAL;
struct cpufreq_frequency_table *table = NULL;
#ifdef CONFIG_CPU_FREQ
table = cpufreq_frequency_get_table(cpu);
@@ -245,12 +245,12 @@ static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq)
if (!table)
return ret;

- while (table[i].frequency != CPUFREQ_TABLE_END) {
+ for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
continue;
if (table[i].frequency == freq)
- return i;
- i++;
+ return level;
+ level++;
}
return ret;
}
--
1.8.1.3

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