In different places in the Thermal code, the CPU frequency list is iterated in an incorrect way, leading to endless loops when the frequency list contains a CPUFREQ_TABLE_INVALID entry, which is the case by default in the the Exynos 4x12 cpufreq driver, for example.
The frequency list is iterated with a while loop, and when a CPUFREQ_TABLE_INVALID entry is encountered, the continue; statement is used to skip it, but the index is not incremented, causing an endless loop. A similar bug was fixed by hongbo.zhang in commit: Thermal: fix bug of counting cpu frequencies Signed-off-by: Gu1 <[email protected]> --- drivers/thermal/cpu_cooling.c | 8 +++----- drivers/thermal/exynos_thermal.c | 9 +++++---- 2 files changed, 8 insertions(+), 9 deletions(-) diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c index 836828e..51acd26 100644 --- a/drivers/thermal/cpu_cooling.c +++ b/drivers/thermal/cpu_cooling.c @@ -123,7 +123,7 @@ static int is_cpufreq_valid(int cpu) */ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) { - int ret = 0, i = 0; + int ret = 0, i; unsigned long level_index; bool descend = false; struct cpufreq_frequency_table *table = @@ -131,7 +131,7 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) 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; @@ -145,7 +145,6 @@ 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) return table[i].frequency; - i++; } i--; @@ -154,13 +153,12 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level) level_index = i - 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) return table[i].frequency; - i--; } return ret; } diff --git a/drivers/thermal/exynos_thermal.c b/drivers/thermal/exynos_thermal.c index 224751e..fa9e1d7 100644 --- a/drivers/thermal/exynos_thermal.c +++ b/drivers/thermal/exynos_thermal.c @@ -233,7 +233,8 @@ 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, ret = -EINVAL; + unsigned int count = 0; struct cpufreq_frequency_table *table = NULL; #ifdef CONFIG_CPU_FREQ table = cpufreq_frequency_get_table(cpu); @@ -241,12 +242,12 @@ 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 count; + count++; } return ret; } -- 1.8.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
