diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 25 | ||||
| -rw-r--r-- | drivers/cpufreq/cpufreq_governor.c | 2 | ||||
| -rw-r--r-- | drivers/cpufreq/intel_pstate.c | 4 |
3 files changed, 20 insertions, 11 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index dd568aa..6eca12a 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -115,12 +115,15 @@ static DEFINE_PER_CPU(struct update_util_data *, cpufreq_update_util_data); * to call from cpufreq_update_util(). That function will be called from an RCU * read-side critical section, so it must not sleep. * - * Callers must use RCU callbacks to free any memory that might be accessed - * via the old update_util_data pointer or invoke synchronize_rcu() right after - * this function to avoid use-after-free. + * Callers must use RCU-sched callbacks to free any memory that might be + * accessed via the old update_util_data pointer or invoke synchronize_sched() + * right after this function to avoid use-after-free. */ void cpufreq_set_update_util_data(int cpu, struct update_util_data *data) { + if (WARN_ON(data && !data->func)) + return; + rcu_assign_pointer(per_cpu(cpufreq_update_util_data, cpu), data); } EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data); @@ -133,18 +136,24 @@ EXPORT_SYMBOL_GPL(cpufreq_set_update_util_data); * * This function is called by the scheduler on every invocation of * update_load_avg() on the CPU whose utilization is being updated. + * + * It can only be called from RCU-sched read-side critical sections. */ void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) { struct update_util_data *data; - rcu_read_lock(); +#ifdef CONFIG_LOCKDEP + WARN_ON(debug_locks && !rcu_read_lock_sched_held()); +#endif - data = rcu_dereference(*this_cpu_ptr(&cpufreq_update_util_data)); - if (data && data->func) + data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data)); + /* + * If this isn't inside of an RCU-sched read-side critical section, data + * may become NULL after the check below. + */ + if (data) data->func(data, time, util, max); - - rcu_read_unlock(); } /* Flag to suspend/resume CPUFreq governors */ diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c index 70079e2..db46190 100644 --- a/drivers/cpufreq/cpufreq_governor.c +++ b/drivers/cpufreq/cpufreq_governor.c @@ -280,7 +280,7 @@ static inline void gov_clear_update_util(struct cpufreq_policy *policy) for_each_cpu(i, policy->cpus) cpufreq_set_update_util_data(i, NULL); - synchronize_rcu(); + synchronize_sched(); } static void gov_cancel_work(struct cpufreq_policy *policy) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index f4d85c2..2165d2b 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -1168,7 +1168,7 @@ static void intel_pstate_stop_cpu(struct cpufreq_policy *policy) pr_debug("intel_pstate: CPU %d exiting\n", cpu_num); cpufreq_set_update_util_data(cpu_num, NULL); - synchronize_rcu(); + synchronize_sched(); if (hwp_active) return; @@ -1426,7 +1426,7 @@ out: for_each_online_cpu(cpu) { if (all_cpu_data[cpu]) { cpufreq_set_update_util_data(cpu, NULL); - synchronize_rcu(); + synchronize_sched(); kfree(all_cpu_data[cpu]); } } |