>
> Signed-off-by: Srivatsa S. Bhat <[email protected]>
> ---
>
> v2: Removed the coverage of ASYNC_NOTIFICATION drivers, in order to avoid
> false-positives.
I am confused - on top of what patches should I test it?
>
> drivers/cpufreq/cpufreq.c | 7 +++++++
> include/linux/cpufreq.h | 1 +
> 2 files changed, 8 insertions(+)
>
> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
> index abda660..afcac67 100644
> --- a/drivers/cpufreq/cpufreq.c
> +++ b/drivers/cpufreq/cpufreq.c
> @@ -354,6 +354,11 @@ 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 */
> + WARN_ON(!(cpufreq_driver->flags & CPUFREQ_ASYNC_NOTIFICATION)
> + && current == policy->transition_task);
> +
> wait:
> wait_event(policy->transition_wait, !policy->transition_ongoing);
>
> @@ -365,6 +370,7 @@ wait:
> }
>
> policy->transition_ongoing = true;
> + policy->transition_task = current;
>
> spin_unlock(&policy->transition_lock);
>
> @@ -381,6 +387,7 @@ 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 5ae5100..8f44d79 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 */
>
--
Meelis Roos ([email protected])
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