| Message ID | 927dcc1de6acad3dd2cfae4e300e6fee4f665101.1549001732.git.viresh.kumar@linaro.org |
|---|---|
| State | Accepted |
| Commit | 9795607dc41e7606e90e48bffe6927bee32cd336 |
| Headers | show |
| Series | [1/2] cpufreq: stats: Declare freq-attr right after their callbacks | expand |
On Fri, Feb 01, 2019 at 11:45:45AM +0530, Viresh Kumar wrote: > It is possible for cpufreq_stats_clear_table() and > cpufreq_stats_record_transition() to get called concurrently and they > will try to update same variables simultaneously and may lead to > corruption of data. > > Prevent that with the help of existing spinlock. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > drivers/cpufreq/cpufreq_stats.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c > index 941e63e3e652..e2db5581489a 100644 > --- a/drivers/cpufreq/cpufreq_stats.c > +++ b/drivers/cpufreq/cpufreq_stats.c > @@ -31,20 +31,20 @@ static void cpufreq_stats_update(struct cpufreq_stats *stats) > { > unsigned long long cur_time = get_jiffies_64(); > > - spin_lock(&cpufreq_stats_lock); > stats->time_in_state[stats->last_index] += cur_time - stats->last_time; > stats->last_time = cur_time; > - spin_unlock(&cpufreq_stats_lock); > } > > static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) > { > unsigned int count = stats->max_state; > > + spin_lock(&cpufreq_stats_lock); > memset(stats->time_in_state, 0, count * sizeof(u64)); > memset(stats->trans_table, 0, count * count * sizeof(int)); > stats->last_time = get_jiffies_64(); > stats->total_trans = 0; > + spin_unlock(&cpufreq_stats_lock); > } > > static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) > @@ -62,7 +62,10 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) > if (policy->fast_switch_enabled) > return 0; > > + spin_lock(&cpufreq_stats_lock); > cpufreq_stats_update(stats); > + spin_unlock(&cpufreq_stats_lock); > + > for (i = 0; i < stats->state_num; i++) { > len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i], > (unsigned long long) > @@ -239,9 +242,11 @@ void cpufreq_stats_record_transition(struct cpufreq_policy *policy, > if (old_index == -1 || new_index == -1 || old_index == new_index) > return; > > + spin_lock(&cpufreq_stats_lock); > cpufreq_stats_update(stats); > > stats->last_index = new_index; > stats->trans_table[old_index * stats->max_state + new_index]++; > stats->total_trans++; > + spin_unlock(&cpufreq_stats_lock); > } Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c index 941e63e3e652..e2db5581489a 100644 --- a/drivers/cpufreq/cpufreq_stats.c +++ b/drivers/cpufreq/cpufreq_stats.c @@ -31,20 +31,20 @@ static void cpufreq_stats_update(struct cpufreq_stats *stats) { unsigned long long cur_time = get_jiffies_64(); - spin_lock(&cpufreq_stats_lock); stats->time_in_state[stats->last_index] += cur_time - stats->last_time; stats->last_time = cur_time; - spin_unlock(&cpufreq_stats_lock); } static void cpufreq_stats_clear_table(struct cpufreq_stats *stats) { unsigned int count = stats->max_state; + spin_lock(&cpufreq_stats_lock); memset(stats->time_in_state, 0, count * sizeof(u64)); memset(stats->trans_table, 0, count * count * sizeof(int)); stats->last_time = get_jiffies_64(); stats->total_trans = 0; + spin_unlock(&cpufreq_stats_lock); } static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf) @@ -62,7 +62,10 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf) if (policy->fast_switch_enabled) return 0; + spin_lock(&cpufreq_stats_lock); cpufreq_stats_update(stats); + spin_unlock(&cpufreq_stats_lock); + for (i = 0; i < stats->state_num; i++) { len += sprintf(buf + len, "%u %llu\n", stats->freq_table[i], (unsigned long long) @@ -239,9 +242,11 @@ void cpufreq_stats_record_transition(struct cpufreq_policy *policy, if (old_index == -1 || new_index == -1 || old_index == new_index) return; + spin_lock(&cpufreq_stats_lock); cpufreq_stats_update(stats); stats->last_index = new_index; stats->trans_table[old_index * stats->max_state + new_index]++; stats->total_trans++; + spin_unlock(&cpufreq_stats_lock); }
It is possible for cpufreq_stats_clear_table() and cpufreq_stats_record_transition() to get called concurrently and they will try to update same variables simultaneously and may lead to corruption of data. Prevent that with the help of existing spinlock. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- drivers/cpufreq/cpufreq_stats.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 2.20.1.321.g9e740568ce00