diff options
| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-01-19 11:13:37 -0800 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2017-01-22 00:23:19 -0800 |
| commit | e9728f0dd7dc06fb0f0d18552ab9599005cd2ab7 (patch) | |
| tree | fbbf52c9d3f453c52124a01ff93167d589f5f7a9 | |
| parent | 48a55d7de79f95176f3ab372be66165a60be222f (diff) | |
| download | linux-e9728f0dd7dc06fb0f0d18552ab9599005cd2ab7.tar.gz | |
Input: pwm-beeper - fix race when suspending
Usually userspace sends SND_BELL and SND_TONE events, and by the time pwm_beeper_suspend() runs userpsace is already frozen, but theoretically in-kernel users may send these events too, and that may cause pwm_beeper_event() scheduling another work after we canceled it. Let's introduce a "suspended" flag and check it in pwm_beeper_event() to avoid this race. Reviewed-by: Thierry Reding <thierry.reding@gmail.com> Tested-by: David Lechner <david@lechnology.com> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
| -rw-r--r-- | drivers/input/misc/pwm-beeper.c | 21 |
1 files changed, 18 insertions, 3 deletions
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c index 58a60b42c836..9d7987d9ba1b 100644 --- a/drivers/input/misc/pwm-beeper.c +++ b/drivers/input/misc/pwm-beeper.c @@ -27,6 +27,7 @@ struct pwm_beeper { struct pwm_device *pwm; struct work_struct work; unsigned long period; + bool suspended; }; #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x)) @@ -73,7 +74,8 @@ static int pwm_beeper_event(struct input_dev *input, else beeper->period = HZ_TO_NANOSECONDS(value); - schedule_work(&beeper->work); + if (!beeper->suspended) + schedule_work(&beeper->work); return 0; } @@ -154,6 +156,15 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); + /* + * Spinlock is taken here is not to protect write to + * beeper->suspended, but to ensure that pwm_beeper_event + * does not re-submit work once flag is set. + */ + spin_lock_irq(&beeper->input->event_lock); + beeper->suspended = true; + spin_unlock_irq(&beeper->input->event_lock); + pwm_beeper_stop(beeper); return 0; @@ -163,8 +174,12 @@ static int __maybe_unused pwm_beeper_resume(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); - if (beeper->period) - __pwm_beeper_set(beeper); + spin_lock_irq(&beeper->input->event_lock); + beeper->suspended = false; + spin_unlock_irq(&beeper->input->event_lock); + + /* Let worker figure out if we should resume beeping */ + schedule_work(&beeper->work); return 0; } |