diff options
| -rw-r--r-- | drivers/cpufreq/cpufreq.c | 14 | ||||
| -rw-r--r-- | include/linux/cpufreq.h | 1 |
2 files changed, 15 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index a517da996aaf..bfe82b63875f 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -365,6 +365,18 @@ static void cpufreq_notify_post_transition(struct cpufreq_policy *policy, void cpufreq_freq_transition_begin(struct cpufreq_policy *policy, struct cpufreq_freqs *freqs) { + + /* + * Catch double invocations of _begin() which lead to self-deadlock. + * ASYNC_NOTIFICATION drivers are left out because the cpufreq core + * doesn't invoke _begin() on their behalf, and hence the chances of + * double invocations are very low. Moreover, there are scenarios + * where these checks can emit false-positive warnings in these + * drivers; so we avoid that by skipping them altogether. + */ + WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION) + && current == policy->transition_task); + wait: wait_event(policy->transition_wait, !policy->transition_ongoing); @@ -376,6 +388,7 @@ wait: } policy->transition_ongoing = true; + policy->transition_task = current; spin_unlock(&policy->transition_lock); @@ -392,6 +405,7 @@ void cpufreq_freq_transition_end(struct cpufreq_policy *policy, cpufreq_notify_post_transition(policy, freqs, transition_failed); policy->transition_ongoing = false; + policy->transition_task = NULL; wake_up(&policy->transition_wait); } diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h index 77a5fa191502..f3822f836e14 100644 --- a/include/linux/cpufreq.h +++ b/include/linux/cpufreq.h @@ -110,6 +110,7 @@ struct cpufreq_policy { bool transition_ongoing; /* Tracks transition status */ spinlock_t transition_lock; wait_queue_head_t transition_wait; + struct task_struct *transition_task; /* Task which is doing the transition */ }; /* Only for ACPI */ |